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For /3o ^"^ c^^"

Library
Arnold Arboretum

Harvard University

7^ ^^?^2^ CA"^^

THE

.CONSTRUCTION

T I M B E R,/;,

From its EARLY GROWTH; ^

Explained by tbe

M I C R O S G O P E,

And proved from

EXPERIME]SfT5,

In a great Variety of Kinds:

In FIVE BOOKS.

On the Parts of Tries ; their Vessels ; and their
Encrease by Growth : And on the different
Disposition of thofe Par.ts in various Kmos;
and the Particularities in their Vessels.

WITH FIGVRES OF

r Their various Appearances j of the Instrument for
cutting them ; and af tbe Microscope thro' which
they were viewed.

^ By JOHN gILL, M.D. -

Member of the IicfPERiAL Academy.

LONDON:
Printed for the A U T H O R ;.

And Sold Dy R. Baldwih, in Pater-Nofter-Row; J. RiDtir,
in St. Jiune&'s-Street ; J. Novrse, T. Becket, P. Elmslt,
J. Campbell, in the Strand; and T, Davib(, ia RulTel-
Street, Covent*Gar4en.

M.»CCXXX.

-'\

Mid, I

f crx. 1 :i C. Ki>

K„tTvA;?D ttflVERCSm

iNlM^f^y «A>^(4(M> mvttArtf

-J"

[3 J

t mmiu tiitfm^m>''^^'^m^mmm^mmimgmmmmft^^f^Km^l^'^l>^99'^nf^t^t^^W*9^9y9^

INTRODUCTION.

IT is propofed to flicw the ConftruAion of
Timber : the Number, Naturf, ap^ Ofikes

of its iev^^l parts ; and their ?arious ar-

rangemen^ and proportions ia the different
kinds : To point out a way of judging, from
the ftrudure of Trecs^ the ufts which they will
beft ierve in the affairs of life ; and of adding
fomething to their (Irength^ and preservation.

The compofition of the whole ; the variations
iq the difpofition, and the di^rences in pro-
portion of the feveral parts, are, in many of the
fpecies, fo ftrange, and in fome fp very delicate,
that to fee them diftin&ly there are required
pieces of fuch an extreme thinnefs, and magni-*
fyiog powers 9t once fo great and fo clear, that
it were yain to lead men into an attempt of fol-

A 2 lowing

4 I.N T R O D U G T I O N. \

lowing the experithents, without firft acquaint?
ing them with the machine by which the pieces
were cut ; and the Microfcope thro* which they
have been viewed.

The Cptting Engine is an invention of the
ingenious Mr. Cummings. The two or three
ijrft were perfcfted under his own hand j; and
they are now made for general ufe by Mr«
Ramfden.

DESCRIPTION of an INSTRUMENT i

for cutting Tranfvcrfe Slices of W O O D, 1
for MICROSCOPICAL OBJECTS. !

A A. Plate L Fig. i. reprefents a cylinder of :
^vory, three inches and a half long, and two ,
inches in diameter ; to the one end of which
is fitted

B B. -/f plate of bell-metal ; the feftion of ;

which, with the maimer of fitting it to the

ivory, may be feen in Fig. 2. in which the .

feveral parts are marked with the fame letter?

as in Fig. i ,
*' *

C* is ^ plate of brafs, fitted to the Other end ■
f[ the cylinder ; through which and the ivory

there

. I N T R 6 D U C T I O N. $

there piis two long fcrews^ which take into the
thick part of the beU-mctal B B, fo as to fix
both plates ftrongly to the ivory; into which
they are alfo indented, to prevetit fuch fhaking
as might otherwife happen after fwelling pr
ihrinking.

D D. TAe Cutter 5 whofe edge is a fpiral, and
the difference of whofe longeft and (horteft radii
is equal to the thicknefs of the largeil piece of
wood that the inflrument will take in. The
loweft fide of this cutter muft be ground ex-
tremely flat and true, in order that all the parts
of its edge may be exactly in the fame plane ;
and that the middle part of it may be applied
dofely to the fiat circular plane left at the center
of the plate B B, to preferve it iii the proper
direction when carried round by the handle.

All that part of the bell metal, which ti?e edge
af the cutter traverfes^ is turned fo low as not to
touch it, (fee the Section :) the middle of the
cutter is about « of an inch thick, and has in it
a fquare hole that fits on the end of a ftecl axis
P P, one end of which turns on a pivot in the
plate C, the other end in the plate B B. This
end has a conical (houlder which fits into a hole

? q£

6 INTRODUCTION.

fame iflialpe iti the tuider fide ^f the ^late,
atr i«(>i«feftted in the Sediom

« e, A piect (f brafs fiihe^vhat in the fm
Hh indext which is ftlfo pikt on the axi« P P
^s piece has a rouod hole hi ks celitet £> fei
as to achnit of its being turned into any j^fitit
tirith regard to the cotter ; afid in (order td keej
it concentric ^reto ^erfe is tfcft on ft a circa]
prdjedion whidi fits iAto H ttfvity itAde in thi
lower ^e of the hitini^ >t^r6 it fits oa tl
aids.. (See the Sedidn.)

F. 7%^ hmtdk ; «4iie^ is fo fi««d M the asi
P P, diftt it cartieS tiift c«tttfr and ithe pieci
■it e round wkh it

G. Jf Nut thM ictievirs ^e handle oti its axisi
"and liee^s the Gutter flat lt> the beU-tttetal 8 Bj
when carried roiiiid by the hiindle,

b V o.^-^Is a bole nearly in fhape of the JiSior
tf circle^ pierced through that part of thfe bcU-
metal which the edge of the cfitt*r traVertfeSi
and continued through th^s whde length of the
ivory cylinder, truly parallel to its axis, and of
an exactly equal width throtkghdut, fill it termi-
nates at the plate a

H. reprefcnts

PI. I

tJ^TRODUCTION. 7

ti. repre(encs tie end of a fiece of wood of
^bid> ^fikes are to be cuty and which is put into
the cavity o o o\ into the suigular.pait of which
it is gently prefled by means of

K K. 7«w. braft fcrewsy which paTs thro* the
ivory into the cavity 009^ and are made to prcfs
on the wood b by means c^

L« A key that fits into hollow Squares, made
in the fcrews K K«

M. Afcrew that paffes thro* the brafs plate C,
43ppofite the middle of the cavity 9 0i and by
jneans of wfcidi the wood b is raiied to the
cotter* This fi:rew has forty threads to an inch,
and its head being divided into twenty ^^five equal
fplces^ it is evident that the moving one of
theie divifions or fpaces will make the icrew
advance and raiie the wood ^ juft one thoufandth
part of an inch.

N. An index that points the divifions on the
head of the (crew (M). The breadth <£ this
index^ fi'om the one fiducial edge to the other,
fubtends a divifion and a half on the head c^^
the icrew^ by which ineans half divifions as
well as whole ones m^y be accurately^ ihiftcd,
and the aoooth, 1500th, loooth, 750th, &c.
parts of an inch truly eftimatcd. To render tbe^

A 4 efFedl

8 INT ROD U C T I ON.

cfFcft of this fcrew the more ccrtiaifl, its point
is turned round fo as to adt very near the center,
and a piece of ivory (fee Fig. 3.) is carefully
fitted into the cavity 000^ fo a:s to move freely
therein without any lateral fhake, and to reft 01^.
the end of tjie fcrew M. This piece of ivory
afting equally on every part of the under furface
of the wood^ will raife it towards the cutter
with much morcT certainty than if the fcrew
afted immediately on it. Several fiich pieces of
ivory, of different lengths, (as reprefcnted by
Fig. 3.) ought to be fitted to the inftrumcnt, fi>
as readily to fuit the length of any given piece
of wood. One piece of the full length of
Fig. 3. niuft have one end left rough fi-om the
file, that pieces of cork, agaric, the pith of
wood, and \fuch other foft fubflances may be
cemented on it with fealing wax i in vvhich caijJ
they can be cut, into dices of a determinate
thicknefs, as well as wood.

Now if a piece of wood, whether round or of
the (hape reprefented in the inftrument at (i6), and
of whatever fuitabic fize, be put into the cavity
coo, and gently preflcd into the angular part
thereof by the fcrews K K, let it be raifed
towards the cutter by means of the fcrew M»

[ INTRODUCTION. •

I ' ■ • .3

i If the handle be turned to the ri^t, the edge ^

cf itxt cutter will advance on the wood, and I

. cut off fuch part as lies above the plane in which

the edge of the cutter moves ; and wheifi the *

* upper furface of the wood is thus rendered flat,

ilices ntay be cu( of any required thicknefs,

according to the number- of divifions that the

fcrew M is made to advance. If the machine

be made with due care, it will readily cut a

thoufand ilices in an inch ; and if the edge be

* * -

good and very well fet, dices may be cut that are
no thicker dian the 1500th or even the 2000th
part of an inch : but this requires management,
much depending on ttie force with which the
fcrews K K pinch the wood.

It is not an eafy matter to procure an edge
fufficiently fine for the above purpofe ; but With
the very beft poffible, thin flices have a tendency
to curl up into rolls, fo as to be unfit for the
Microfcope ; to prevent which, a very flender
fpring is made to pi^cfs gdntly on that extremity
of the flice where the incifion begins, fo as to
keep it flat to the cutter : when this fpring is
fct to its proper pofition, it is fixed to it by the
finall finger-fcrew I. And left the aftion of
this fpring ihould deftroy the flice after it is

wholly

10 INTRODUCTION.

wholly cut, aad in pafliag over the extremity of
the cutter, the piece e e (which turns with the
cutter) is fixed by the nut C into &di a pofitioa^
that in pafling under the ^ing it raifo it, and
fdieves the ilioe at the veiy inftant that the cut-
ter has wholly done ite ofSce : and thus the flioes
are made to hSl into fpiiits of wine, in vftkh
diey are preferved for ufe.

In fome woods the pith fiirinks fo rety fiufl:
diat it is exti^mely difficult to keep it entire in
flices that are thinner than 750 to an inch : to
remove which imper&dtion an kifirument, of
the nattu'c sAxwc deicribed, was made do Oiift its
own icrew at crvery revolution of the l^dle^ ib
that very little time was left for 4he pitii to
ihrink ; as a hqndred flices could eaiiiy be cat in
e minute, and tht pith was as entire as the wood*
This.inftrument had an index, which being iet
to the numbers 500, 750, looo, made it cnt-fo
many flices to an inch. It performed extremely
well, but was judged lefs fit for general uie than
that which has already been deicribed, it being
more complex, and liable to diforder, as well as
more difficult to manage*

The

IN T ROD U CT 1 ON* u

^Ihc compofition of the Michoscope (whicli
^^s mad^y by diredion of the Noble Pet^a whQ
is ^lenfed to be the Patron c£ this Work»
«id its Author i by Mr. Adams, in F)eeC*Screet,
Miy&^ddatical-Intlrumem- Maker to His ^a*-
Jefty) wfll be underftood by the annexed figure.

Kate li.

A DESCRIPTION of the VARIABLE

MICROSCOPE.

A B C, the body of the Microfcopc, contains
two eye glafies at A, a third near B> and a fourthL
in *he conical part B an4 C. The end C (hews
aHo one of the magnifiers fcrcwed thereto.

Hence the body of this Microfcope exceeds
thofe hitherto made, which have only three
glafies; by encreafing the field of view, and the
light 5 as well as affording an occafional oppor-
tunity of increafing the magnifying power of
each particular.objciftglafs: which is performed
by puHing up the part A E, and the outward tube
A B : the firft fcparates at A, the other at B.

Another advantage attending this inflrument
is, that any two of the magnifiers may be ufed
at the fame time ; in this manner : fcrew the

z button

IX INTRODUCTION.

button i to the part c of the- button a, and then
fcrew both together into the body at C; the
magnifier there represented being firft removed.

There are fevcn of thefe magnifiers ; two of
which ace fhewn at a and i: alfo fix filvcr
fpecula, each having a magnifier adapted to the
fociis of its concavity ; one of which is repre-
fen ted at e 5 thefe are to be fercwed occafionally
to the body at C. Every one of the feven but-
tons, a b, may alfo be ufcd with any one of thefe
Ipecula, by fcrewing the lower part of the frujp-
trum of a cone, which is figured at d, upon the
prominent fcrew on the filver fpcculum at e,
and then fcrewing the ^ part c of any button ^
into its upper end, and all together into thp
body at C.

Note^ The glaflTes are marked i, 2, 3> &c.
and the lead number is the greateft magnifier..

The body of the Microfcope A B C is fiip-
ported by an arm F, into which it may be put
or taken out occafionally, and may be faftened
by the fcrew f. This arm is fixed to the bar
G G, which may be raifed or depreflfed by turn-
ing the large ivory head I, (the fcrew at H being
firft difcharged.) G G Hides clofe to the upper
part of ^ the long bar K L, which laft is firmly

fixed

IN T R O D U C T I O N. 13

fixed at N and N to the tooth-wheel N O N ;
this wheel is fnpportcd by four fcroles whofe
extremities are conne<Sed to an horizontal circu-
lar {^te n^ which gives an horizontal ntiotion to
the wheel, the bar, K L, and every other part
of the Microfcope which is connected thereto ;
the whole being fupportcd upon the pillar M
by the three feet P P P.

The annexed figure of the Microfcope is deli-
neated from its perpendicular pofition, being that
which affords the bcft reprefentation of its fevcral
parts; but there will be no difficulty to conceive,
that on turning the key S the pinion that works
in the teeth of the wheel N O N will give the
bar K L, With the Microfcope and all its appen-
dages, any obliquity or inclination that may be
fequired.

The ftage, D D D, with a hole T in the
middle, is defigned to place objeds on for ob-
fervation ; thefe being firft fixed in an ivoiy
Aider, No. i. or upon a flip of glafs, No* 2. or
they may be placed upon one of the round glafles
which are fitted to the hole at T.

The concave mirror Q^Q^turns vertically
on the extremities of the femicircle g^ and hori-
Sfontally in the cylinder b^ by which means it

may

14 I N T R O D U,C T I O N.

may be dir&ddd ib as to refie<!t the light thfo'
the center of the ftagc at T, and thence thxo'
the body of the Microfcope to the eye at ^l.

Th<^ ftage D D hath z conical pin which fits
4 hole in the Aider W, in which it may be
turned iideways, fo as to lex^mine any t^bje^ too
large for the field of view.

The forole A R has alio « conical pin fitted tQ
a hole in the Aider V,

By nf>ean3 of the Aider W the ft^ge D D n>5y
be readily fet to its proper diftance from the
magnifier in the button at'C> and then by turn-^
ing the large ivory head I, the body of the Mi-^
crofcope may be brought to its diftind focus^
If this be not thought quite fufficient^ tighten
the &rew at H ; and then by turning that at X
it may be adjufted to the eye of any obfcrver
with the greateft precifion, and by the help of
the Aider V a proper^ fpot of light may be readily
obtained r

No. 3. is a cylindrical tube^ in which ^0 in^^
ner tube i is forced upwards by a fpring : its uie
is to receive an ivory Aider No. i • or a glafii
Aider No. 2. the objed being placed in the
center of the hole at «r, and the Aider put
between the plates Jb and /• The hdUow at k

INTRODUCTION. 15

n to receive a glafi tube for confining a fmall
water animal, to fee the circulation of the blood*

If the animalcula in fluids a^ e under confi-
deration^ or any very ipinute infe£t, it will fomci*^
times be neceffiiry to exclude part of the light
which is refleded from the mirror Q^ putting
tl^ pone Na 4* upon the bottom i c^ No. 3,
it bpiiig firft put into the ftage at T.

The nippers. No* 5. are for confining any
pfa^e<ft> and are to be placed in one of the fmall
holes near the extremities of the ilage, or in
the focket r, at the end of the chain of balls.
No. 6. as the pointed nippers /, which hold za
ppaque obje<5l; / v. The ftage D D being re<«
moved, and one of the filver fpecula fcrewed
to the Microfcope at C, the Aider W brought
near to the Aider V, the ftem x of the pillar
belQti|ing to the chain of balls being put into
the hole at W, the balls may be readily managed
to give a proper diredion to the objcdi: v t, an4
ibt obfcrver s back turned to the window, {q
that the refledlion from the mirror of the flcy
behind or one fide nxay fall upon the filver (pecu'*
|um, and thence be returned upon that part of
tj^e objeia t V v^hich \s to be examined.

No. 7,

i6 I N T R O D U C T I O N.

No. 7. is a box containing iparc tajcs, to
fupply the ivory Aiders. J

No. 8. is a double convex lens, to be uied
as a magnifier in the hand.

Laftly, Remove the body A B C» and put
the ftage D D into its place in thfe arm F; put
the pin of No.. 9. into the hole at z, in the
top of .the bar K L ; place an objeft upon the
ftage ; ' and any one of the magnifiers before
defcribed may be fcrewed into the end e of the
Aiding bar e g.

In this fiiate of our variable inft:rument we ,
have a Angle Microfcope to which the above '
apparatus is apj^able: three magnifiers are
added) to be ufed only in this application.

There are likewife added to the apparatus,
two gkfs planes broader than that of No. 2^
and two others' with hollows ground in them.

Alfo a few Aat, round glafifes^ of different
colours,' which fit the hole T in the ftage D D :
and a watch glafs, fitted to the fame place, for.
•ibferving the animalcula in fluids ;

And a fet of glais tubes.

THE

^«

r >7 ]

^_ t

• 'the

CONSTRUCTION

T I M B E R

EXPLAINED BY THE

MICROSCOPE.

BOOK 1.

Of the conftituent Parts of Timber.

CHAP. I.

Of the Number of Parts in Trees, and
the Manner in which they are difpofed.

THE compofition of Wood is beft feen
in a Shoot of two years and a half
growth : and the moft diftindt and
pleafing view of the feveral parts, as they lie
together, is to be obtained by placing a very
thin flice, qut tranfverfely from fuch a Shoot,
before the iSifth glafs of the reflecting Micro-
fcope,

J3 Greater

i8 The CoNtxRucTioN of Timber

Greater Powers, and another Apparatus, will
be required for the examination of every part of
this compofition, feparate ; but before we enter
upon that enquiry, it is beft to take this general
view of all together.

The whole Slice confifts of ieveral concentric
Circles, of different fubftance ; vnAi vefTels^ alio
of different kinds, interfperied among them*

The Parts are thefe :
!• The Rind.

2. The Bark..

3. The Blea.
^. The Wood.,

5. The Corona, or Circjle of Prqpa*

cation.

6. The Pith.

" Thele lie imniediately within, or under one,
another : and in, among, ;and between thefe, are
difpofed the Veifels, which feed the whole ; and
fome of which contain the juices, that give the
H3rce its peculiar qualities, and v^tue$%

I t

Bx#t.Ati«Ef> BY ¥fi4i Micito«ceK. I^

T^kiSk y-afSAi at*6 ef five kinils t
4. The ElttEliioJi j

4fe. The IlttEltlOR * > jOT€E*Vt«SfeL*k

3. irbe liatiMATE 3

4. The SAf-VEs«Ei,<,
5i The CorWa'L*

O^ thefe> thfc *ril arc phccd bctwcea tke

Rimi aAd Bark ;
Hie fecond, in the fubftaricc of the B^rk $
The third, in the fubftance of the Blea ;
The fourdiy in the fubftance of the Wood j
The fifth, 4n the C(»rona^ or Circle of Rro*

pagation* ^

Befided fhefe greater Veffels, the fcreral parts
themfelves are vafcular ; but their Tabes are 6f
another kind ; and will be confi4^red when we
examine the conftruftion of thofe feyeral parts.
Other Glaffes will be required For this : they
Ibarce appear in the prefent View j which is
limited folely to the arrangement •£ the eqa**
ftitucnt parts together.

i$o The Construction of Timber

The tree in which thefe feveral circles lie in
the happieft way fpr obfervation, is the Scarlet
Oak of America. If a ilice be cut from a two
years and a half Shoot of this tree, in May s
the parts and vefTels jufl: enumerated will be feeti
as they are reprefented in Plate IIL and this
with great diftindnefs and precifion. Where
this tree is not at hand, fuch a flice of the
cohiifton Englifli Oak will very well fupply
its place, the parts lying nearly in the fame
manner.

> 4.

c reprefents the Rind, dry, and very thin*^

^, the exterior Juice-veflels. Thefe are placed
in round clufters ; they are woody ; and contain
a thin, whititti, watery juice, of no tafte,

r, the Bark. This confifts of a multitude of
filmy bladders, ranged in circles," one behind
another : they are elliptic, thin, an4 browniili ;
and they hold alio a watery juice. They are
connedted together, and arife in thefe circles one
behind another.

</, the

Explained by. the Microscope. 2i

d, the interior JuicQ-veffels. Thefe are ar-
ranged in oval clufters, a very confidprable num-
ber of them together. They are of ^ many tiiries
the diameter of the preceding : their coats are
woody ; and they contain a thicks gummy,
brown juice, of an auftere, ftyptic tafte. This
gives the virtue to the Oak Bark, as ^n aftrin-
gent ; and its quality, fo ufeful in tanning animal
hides.

e reprefents the filea. This confifts of con-
nected circles, which have, in fo thin a piece,
viewed perpendicularly, a great deal of the ap-
pearance of the bladders in the Bark 5 but they
are in reality of a different nature, as we fhall
fee, when each part is examined feparately:
thefe circles *e indeed tranfverfe fc<5lions of
elliptic vefTels, arranged clofely fide by fide to-
gether. They are equal in their whole diameter
to the bladders of the Bark ; but their cavity is
much lefs, becaufe their fides are thick.

y ihews the intimate, or moft inward Juice-»
velTels of the Oak : they are fome\yhat larger in
diameter than the conftituent vefTels of the Blea ;

B 3 ^ and

I N

%% The CoNSTRVCTidii of Timtt:

and they ftand fingly^ not in clufters^ as the twa
farmer : they contaiA a d>ick and ahopft oon-^
creted brown juice» more aiiflere thaii that io
the veiTels qf the Bark : and it is from, thefe th^^
wood of the Oak. pofTeiTps the :6une aoftere aa4

j^« In the whole ipace fronx gttagz we
f^e the Wood. Thia is compofed of five con^
centric circles, terminated by fo niany imdulatecl
lines. Thefe are the feveral coats of Wood>
added from feaibn ^ feafoo. It haa been iiip-
pofed that: each cifcle is tho, growth of ;a year ;
but a careful attention to the eAcreaj(e of woi^d
\jM fhewn mt% beyond a dpubt» th^at two fuch'
^ro forlihed each year ; the one in Spring]^ the
other foon after Midfumper. At eaph of the^
times ikp l^aneh (hoots oi^t w length; and
whenfoever that is done^ the Shoot of the |ire-
^eding feafon gets an additional coat in thicks
neis : I ihall therefore be permitted to call theih,
inftead of Year Cirdks, Cireks of the Seafcm^
The Branch from which the prefent fe^ion was
taken, having been of two. years^ a^d a half
||rowth» there are fc^nd ^ U $ve ijath circles*

^ ' The

£kpi.ainbd by the Microscope. 23

The compoiltioQ.of the Wood is of veflels
haii obliterated, by the growth of their fides
£Uiag up their, cavities iawardly ; and fwelling
Qut in die £une mlaner externally. The whole
interftitial (pace being thus filled up, the very
ibrms of them zfc by degrees loft.

At ^ are ihewa the Sap-vefTels of the Oak.

Concerning which, there have been flrange mif-f
takes.^ But it is not my purpofe to point Out
wbefe others have erred | only plainly to lay
down what I have ieen, and what the objodls
themfdives ore ready to make evident to every

OOP,

m N

Thcfe vefTels arife in the fubftance of th^
Woody principally towards the oqter edge of
each cirele. They are very large in the outer^
snofkcozt ; and finallerin the others : and there
are alfo irregular ranges of them, running thro*
the thicknefTes of the circlels; belide thefe prin-
cipal oi>cs of the outer courfe. They have
£>lidy and firm coats i and they contain in Spring,
and at Midfummer, a limpid liquor, like watir^
Jmt with a flight acidity : at all other feafons of

3 4 the

24 The Construction of Timber

the year they, appear empty, th^Ir iides only
being moiftened with the fame acid liquor.
Thofe who examined them at fuch feafons,
thought them air-veflels ; and in that opinion,
formed a conftrudlion for them, which Nature

does not avow.

« •

A
I
I

/ fhews the Corona, or Circle 6f Propagation j

a part of the utmoft importance in the Vegetable

I.I

Oeconomy ; fince from it arife the branches, and
cncreafe of the tree ; no Vegetable is without it;
nor have the figures of thbfe, who have drawn
the parts of Plants, failed to exhibit it, as a
portion different from all others : yet, till this
occafion, it never had a name. It is in the Oak
an undulated circle ; and the undulations of all
the other circles take the^^r rife from it. It con-
tains diftintSlly two kinds of yeflels } a larger, /t,
which are pale ; and a fmaller, which arc
browner ; together with an intermediate mat-
ter : this laft is not vafcular, but compofed, as

■< >

the bark, of filmy bladders. The larger order
of veffels contain a fomewhat acid jiiice; the
fmaller order, a very auftere liquor; and the
intermediate fubflance, pure water.

/ reprefcnts

O^ic ^'-^

, \\ '■■■ s

Explained »y the Microscope. 25

/ reprefcnts the Pith. This takes the famei
undulated form in its outline as the Corona,
which every way inclofes it : its appearance is
very pretty : it fcems to confift of rings, with
fingle, double, and interfering outlined ; but the
reality is otherwife. The whole is a compages
of little, hollow, white films, arranged, fide by
fide, acrofe the entire fpace, and having others
of the fame kind, and form, beneath themj
through the whole length of the iShoot.

m fhews the entire Slice in its natural bignefs.

Such is the conftruftion of a Shoot, and fuch
the difpofition of the feveral parts: we may
now proceed to their feparate examination.

G H A P.

»6 Ths Qwmvcsi^m or Timb«k

mmm^^mi^tumm'^mmm^titmimmmmm^tmmmmdmm^mmmmmmmmmmm^mmmmi^m

CHAP. U.

TBc Manner of ofctaming the PxitTf
of a Shoot "feparate,

^[^H£ onquir^ iato tiks . ftruiSkurc q£ «ach
feparatc part of the Shoott is a matter
^ much greater car^^ and atttotioa thaa the
former : I will not %» of difficulty i Ibr every
tmng yields to a detecmlaed* mindr bu& lime
^nd application will be required* The method
I have ufed is this ;.

, In the beginning of April I take a quantity
of young branches, from the Scarlet Oak, and
other trees. Thefe are firft cut into lengths, of
the growth of different feafons i and then part
are left entire> part fpHt, and the reft quarteredt
In this ftate they are put into a wicker bafket,

^ vith

Explains]^ »y ths Mics:i3sx:or£. 37

with largs openings, or of loofe work ; aad a
heavy ftooe 19 put in with .them : a. rope is ti94
to th& handle of the bai&.et> and it is thmwn
ijQto a brook of running water : at times it is
taken up, and expofed a little to t^ie air; it
is frequently fhook about under water, to wafh
off filth; and once in ten days the fticks are
cxaixiinetL . ,

By degrees, the parts loofcn from one another 5

and, by gentle rubbing in a. bafon of water, juft

warm'd^ they will be fo far feparated, that a
pencil brufh will perfe<3: the bufinefs ; and ajfford
pieces of various fize» pure, diftinft, and clean*
One part will„ in this way, fepai?ate at one time,
apd another at another : but by returning the
fticks to the water, and repeating the operation >
io a courfe of four or five weeks, every part
may be obtained diftitidt. They are beft ex-
amined immediately ; but as one Wifhes to pre*
jferve them for repeated enqiiiries^ it may be done
ia thisr msnner.

. Piflolve half an ounce of Alum in two quarts^
of water: .drop the pieces, thus feparated, for a
few moPBients, into tl^is folution ; then dry them

upon

28 The^Construction of Timbejr

, upon paper, and put them up, in vials of Spirit
of Wine. Nothing but Spirit of Wine can pre-
ferve thefe tender bodies ; and, till I found this
method of hardening them firft, that liquor often
deftroyed them.

C H A P. III.

of the, Construction of the Rind.

IT has been cuftomary to diftinguifli the two
outermofl: coats of a tree by the names
Outer, and Inner Rind ; but as we have the
two^ vsrords, Rind and Bark, in common ufe, it
may be more diftinft to apply One of them to
the one,' and the other to the other.

The Rind, or outermofl: coat, being feparated
from the refl:, and cleaned, appears before the
Microfcope like a piece of a white cobweb.
It is to be, examined, if frcfli, in water ; if pre-
ferved, in fome of the Spirit wherein it is kept ;
being laid in a little ciftern, hollowed ih a flip

-. Ad

. Explained by the MiCRoscdPE. 29

of ground glafs.- The happieft view of it will be
had by combining the fixth and feventji magni-
fiers of the Microfcope here figured.

Although tills Rind be by far the thinneft of
all the parts, yet it is compofed of feveral coats }
one laid clofely over another, and all of the fame
kind : the great difficulty is to obtain one of
them abfolutely feparate. In that ftate it appears
fcarce more than a fhadow, or a mere delineation
of lines upon the glafs ; but without this, its
true conftrudtion cannot be known* '

The piece of Rind reprefented at Fig. i, in
Tab. ly. fhews the neceffity of this exadtnefs :
the part of it at a is one coat only ; at i, two
lie over one another ; at c, three : in thefc two
laft portions therfe is a great deal of confufion :
but at ^ the real flrufture of the part k perfectly
diftinft. It confifts of a feries of Ipngitudinal '

veflels, and a filmy fubftance between them^

• ■

It, might feem that there are alfo tranfverfe veflels
going at fmall diftances from one of the longi-
tudinal ones to another ; but this is a deception :
a clofe examination will fhew,. that thefe are
only fpaces between part and part of the film.

A larger

JO Tftt CoNsmucTioM of TlM%tlt

A larger power of m%mfymg being \ifed, fcf
changing the fixth for the fbufth objeft gkls»
flill keeping on the feventh, we (hall fee the
difierence between ihefe empty fpaces und a ^f*
colar fttuftuK, very plainly, ee AC Fig. 2. /•

To uiidetibind rightly whst the filmy paiti g^
the Rind is, we muiH return to an ^caminatloii
of the ttanfverf^ feflioni which was firft viewed*
In this we (hall fee, that tbs parts between vef*
fel and veflfel reprefent &e mouths of open,
oval cells : and, referring this appearance to the
view here given at Plate IV. Fig. i . we fliall
underftand that each film, between fpace and
fpace, is - an oblong bladder j which the knife,
in the tranfverfe fe<3:ion, has^cut through. One
of thefe bladders, feparate, is reprefented at^
Fig. 4. At g-, Fig. 5. are three or four,, with
their intermediate fpaces, and with the longi-
tudinal vefTels continuous between them: this
makes a piece of one coat of the Rind; and ts
>>a true and exaft view of its compofition. In
Herbaceous Plants, two films enclofe the whole f
but it is not fi> in Trees*

C HAP.

'^S^

Es:tLAi^2h BY THt Micaiotcoi>t.' ft

Miia«ari**iMaMaaMlM«MaMaa)Ma«M*MM^

CHAP. IV,

Of the Uses oF tlieRiNDt

THE Rind) as dim as It is, and as incoii^'
fideralfe as it may feem^ is a part of the
vegetable itniAare» of the hightft and moft tC^
fential ufe : it covers the whole tree> both above $
and, what is much more important^ tinder the
grour^; and cdntains the great and original
organs by which it grows.

To take a right view of its hnportance and
utility we xAufl: obferve fome yet unnoticed parts
of its conftruftion : and that thefe may be ren«
dered more difHnft than in their ftate of nature»
*tis proper to convey coloured fluids into the
feveral veffels. The divifibility of matter has
bccri pfteii fpofecn of with wonder, but tt has^

2^ never

32 The CoNstliucTioN of Timber

never been maniiefted to the fenfes in a degree
at all to be compared with what is exhibited by
iuch impregnations of vegetable parts.

It may be now obferved, that at the letter g
in Fig. 4. there appear dots upon the highly
magnified veffels : but to know what they are
requires yet greater powers of thq Microfcope,
and more afliftance. There are fcarce ahy limits
to the degrees of magnifying that may be ob-
tained by the combination of two objeft glaffes,
of different powers, as the conftruftionof this
Microfcope admits : nor are the means of more
afliftance wanting ; fince coloured liquors may be
thrown into the fmall veflels of Plants : nay, and
into the very fmilleft of all, liquors, which itho'
pellucid and colourlefs when received, may be
coloured after they are lodged there ; altho* the
matter of that colouring would have rendered
the liquid too thick to have pafTed in the fame
condition.

As the veflels of the Rind arc of different

■

diatneters in various trees, tho' their conftrtidlion
and that of the Blebs is perfectly the fame in all ;
it will be beft to choofe for this purpofe the Rind

ESctiAlSED BV THE MlCROSCOPi.^ 33

of* a tree wherein they arc largeft* The advan- v
tagtfs I receive from the garden of her Royal
Highnejs the Princefs Dowager of Wales, at
Kew> (who> beft of Princeffes and of Women !
is pleafed, u'ndeferving as I gm, to honour me
with her royal patronage and protedlionj) that
garden, where every tree that has been feen in
Europe is at hand ; have given me opportunities ,
of fo many trials, that I can happily fave the
pains of others in this and all the following
inftaiices ; by faying what beft anfwers. To the
prefent purpofe the Rind of the Afh-leaved
Maple is finely fuited. ,A piece of this may
be obtained of two inches long, and will very
' iuccefsfuUy anfwer the intention* Such a piece
being prepared without cither alum or fpirit,
but dried from the water in which it had been
macerated, is to be impregnated with lead in
the following manner ; to fhew the apertures by
their colour.

Diflblve one dram of fugar pf lead in aa
ounce and a half of. water : filter this thro*
paper, and pour it into a tea-cup. Clip ojff a
thin flice pf what was the lower end of the piece
of Rind^ as it grew on the tree, and pluqgc it

C near'

34 * The Cokstrvction of Timber

near an inch deep in the.liquof; keep it upright
between two pieces of flicks fo that one half
Cf more n^ay be above the water: whelm a
wine and water glafs over the tea-cup, and fet
the whole in » wami place. When it has ilood
two dayst take it out^ and clip off all that part
which was in the liquor* and throw it away.

The circumflances here mentioned, trivial a&
they feem^ muft be attended to : the operation
will not fi\cceed even if the covering glafs be
omitted : it keeps a moift atmoiphere about the
Rindj and makes its vefTels fupple.

While this is (landings put into a bafon iwa
ounces of quick lime> and an ounce of orpiment ;
poflfr upon them a pint and a half of boiling
water ; Air the whole together ; and when ii
has flood a day and night, it will be fit for ufe.
This is the Liqupr Probatorius Vini of fome of
the German chymifls : it difcovers lead whea
wines are adulterated with it ; and will fliew it
any where.

Put a little of this liquor in a tea^cup,. and
plunge the piece of Rind batf«way into it.

£jfPLAlNE& fiV tun MiCllOSCOPE. 2S

' ' I

In the former part of this experiment the
Veflels of the Rind have been filled with a folu-
lion of lead; that makes of itfelf no vifiblr
alteration in them : but this colourlefs impreg*^
nation^ when the Orpiment Lixivium gets to \%
becomes of a deep brown: the vefTels them<^
ielves appear fomewhat the darker for it ; but
thefb dots^ which are real openings^ now are
feen to be plainly fuch, the colour being per*
fe&ly vifible in them, and much darker than in
the veffels. Plate V.t\^\. db^

\ m

This objed muft always be viewed dry, dnd
Is beft kept in one of thofe Sliders which the
Noble Perfon, to whom, in a manner, all tlM
are called my Improvements arfc originally owing,-
has directed to be made with glaiTes inftekd of
Talcs*

If a piece of the Rind, thus impregniited, be
gently rubbed between the fingers till the part«
are feparated, we (hall be able in one place or
other to get a view of the veffels all round,
and of the films which form the Blebs between
them. Thefc laft confift of mere mefiibranc i

»■■-.

36 TtfR Construction of Timber

no power of thfe Microfcopc fliews any thing
yaicular in their ilru(fhire : they are a kind of
bladders, clofed at bottom and open at the top^
with a fpace, greater or lefs, between the top'of
one and the bottom of another. Fig. 2. a a.

As to the Vefiels, their coinpofition is Ofiuch
more to be regarded; they are every where
pierced with openings i but of thefe the outer
ones firft feen, are by far the largeft : there are
two other feries of them j the larger of which,
tho' flill much kfs than the former, are placed
againft the interftitial fpaces, between Bleb and
Blab ; and the fmalleft open into the Blebs them-
felves. Fig. 3. ^ ^»

I ftiould think it is not eafy to err as to the ufes
of thefe openings j when we feie their conftruSion
fo exadtly : and thofe ufes being underftood, we
fliall have made no fmall advance in the know-
ledge of vegetation. Let us, if you pleafe, phi-
lofophic Reader, confider them firft in that part
of the Tree which is under ground, the Root :
here they are always furrounded with fome de-
gree of nioifture: let us, together with thefe
objeds, confider thofe everlafting agents heat and

cold;

Explained by the Microscope. ^7

cold 5 not to fay heat in its various degrees, for
that were fpeaking too abftrufely. Heat can be
nb where prefent but it expands fubftances : cold
no where but it contrails them.

We fee a Root, equalling more than a third
part of the Tree above ground, in the extent of
its furface ; "^ this furf^ce is covered with the
Rind, thus pierced; which is connefted alfo
with the parts underneath it. The cold of
winter contrads the whole i the parts are drawn
cloier together ; and the mouths of thefe in-
numerable veflels are fliut, or nearly (hut, by
this contradion : a little, and but a very little,;
of the half-congealed moifture of the ground gets
into them. This fuffices for the fervice of the
Tree, when there is little heat alfo to caufe per-
fpiration; and when in the decidupus Trees,
(the far greater part of thofe of our country)
the very organs of the greateft perfpiration, the
Leaves, do not exift.

The warmth of fpring arrives : the fluids of
the earth grow thinner, every part of the Root
expands ; this opens the mouths of the vefTels,
and the torrent of nutrition ruftics in. A grfeat

€3 deal

—-r-r'

.*^'

38 Thr Constkuction of Timber

deal of it afcends, but more difFufes itfelf among
the circumjacent parts : the mouths of the fecond
order deliver out a great deal to all the interftitial
ipace ; and thofe of the third into the Blebs
themfelves ; and thefe being naturally open, foon
run oyer. Thus every part of the Rind, and every
coat of it| and even the interftitial (pace between
its innermoft coat and the Bark^ are filled with
a iine fluid ; wd the whole is fupple ; and it then
eafily feparates from the under coverings.

The very courfe and progrefs of the fluid may
be (hewn in this part, even by an cafier pre-
paration : only that different Jlinds muft be
fought for this purpofej the veflels in fomc
being larger than in others. Repeated trials
have (hewn me that the whole progrefs may
be eafily marked in the ^ three following kinds j
with only a tin^fture of cochineal. .

Put half an ounce of cochineal in powder into
half a pint of fpirit of wine ; fet it in a warm
place, and (hake it often, for four days ; then
filter oflF the clear tinfture. Put an inch depth
of this into a cup ; and fet upright in it pieces
of the Rind of Aih, White Willow, and Ozier ;

prepared,

ExipiAiNED BY THE Microscope. 39

prepared, as has been direfted, by maceration
in water ; for in that way one trouble does for
a hundred kinds. Let an inch of the Rinds alio
ftand up out of the. tindlure. After twenty-four
hours take them out, clip ofF the part which
was immerfed in the fluid, and fkve the reft fo|:
obfcrvation.

H«e is a farther inftance of the divifibility of
matter. Tho' colour difappears in a great mea-
fure under the Microfcope ; the more as the
pbwcr of magnifying increafes ; yet in the firft
of thefe Rinds, that of the common Afli, the

courfe of the vefTels^is very'diftindly and beauti-

— ^

fully feen by it 5 for they and they only are crimfon.
in this Ipecies the colouring liquor enters only
by the open ends of the veflels ; for the mouths
at their fides feem too much contrafted in the
drying to receive it : it afcends their whole
length, and. fliews itfelf at the exterior apertures
or mouths, but penetrates no farther. Fig. 4.

In the Willow Rind, fliewn at Fig. 5. the
interftitial ipaccs, as well as the veflels, are^
crimfon : therefore, among the' vaft variety of
conftrudion among the Rinds of fcveral trees^

C 4 the

40 The Conitruction of Timber

the mouths of the fecond feries are in this larger
than in the A(h. It rouft be fo ; becaufe the
colouring liquor was the fame to. both, and only
the conilrudion of the body itfelf could in one
inftanc^ have adniitted it through pafS^es which
were clofed to it in the other.

In the Willow, the apertures of the third
order i^ill refuiing pafTa^e to the coloured fluid,
' the Blebs retained their natural Olive complexion i
but 'tis not fo in the Rind of Ozier, there every
feries of mouths are open enough to let out thp
crimfon liquor, and the whole fubftance of the
Rind is ftained with it. Fig. 6.

From hence Philofophy will judge (and it will
judge with fafety) why. the leaves of the A{h
appear later than thofe of the White Willow,
and why the Open Ozier precedes even thefe*
Elder and Goofeberry Rinds admit this univerfal
tinge more readily th;in Ozier ; but they are not
fo eafily feparated and prepared. The fame
philofophic truth arifes alfo here : their texture
is the openeft of that in any Rinds ; and 'tis
therefore they appear the heralds of the Spring,
god harbipgers pf every other verdure.

CHAP,

I
I

Mind wits fjIiLI) yxssELS -_. '^'

Ni ■

EXPLAJINED BY THE MiCROSCOFI. {(il

» » • •

* *

CHAP. V.

Of the Bark.

( V • • 4 > i «

^'^ HE Bark very much refembles the Kind
1 ' ih its c6nftru(9!ion : nor can it indeed dc
fedtlMrwire ) for the Rind was once Bark^ and Has
only fuffered a flight chapgd in feparating $*om if.
, Happily the conftrudtion of this eflcntial part
viis better feen in the inner than in the outer coat
of Trees ; for it is niore entire, more perfeiSi; j
^and though, in order of place> the Rind could
not biit be firft defcribed, it may be avetrea,
that unlefs this be firft viewed, the compofition

of the other will be very difficultly diftinguiflied.

it'.'.' ' '

■■■ The Tree in which I have found the Bark
moft happily formed for preparation, and for
bbfervation, is the Vine. A piece of this, fepa-
Vated by maceration, and obtained pure and free
froni eviry other fubftance, appears as at Plate

yi. Fig. tr

»-'^"'*-»*' '»*-^' it

'42 The Construction of Timbeii

It confifts plainly of veiTcls^ a ; Blebs^ b ; and
intermediate Tpaces, c. The obvious difference
between this and the outer Rind is, that the
Blebs are longer, and the veffels appear more
tender. , This Bark, which we examine, is one
time to be Rind : the Rih4 that covers it is to
fall off; this is to Separate from its inner coats»
and be . expofed to the ^ir in its place. ; and in
this feparation the Blebs flirink in their length,
and the more immediate contact of the air gives
a rigidity to the veffels.

Little need be faid farther of this y the former,
which is the fame fubftance in another con-
dition» having been defcribed at large. It will
be plain they are the fame when the piece is
applied to a greater microfcopic power : the
mouths of the veiTels are thus fhev^rn yet more
diftindly in this than in the other ; becaufc they
are here more perfect; and the conftrudionof
the Blebs and their abfolute feparate dilpofition
is better feen^ ^becaufc they fland here farther
afunder, the mterflitial fpaces between Bleb and
Bleb haying been made fmaller, as the Blebs
were fhorter by the contradlion. Fig. 2,

A Bleb,

-B^RJC

\ 3

Explained by the Microscope. 43

A Bleb, in its natural condition in the inner
Rind, is ihewn at Fig. 3. It is a cylinder, cloib
at the bafe and open at the mouth, as is the
nniverfal conArudtion of all Blebs of the Bark
and Rind. .

At Fig. 4. is given a tranfverfe fedtion of the
Bark, by which its whole compofition is feen to
be nothing more than a number of coats, ccnn-
poied each of one row of Blebs, with veflels
at their fides, laid very regularly over one
another.

It happens that in the Vine the Va£t interiora
are very diftindit, and very beautifully difpofed.
They will be fpoken of at large in their place :
but it may not be unpleafing to the Reader to
take a view of them, as they are arranged in the
fubftance of the Bark of the Vine. They are
here reprefented at Fig. 5. where a a fheiys the
Bark, and ^ ^ the cluflers of thefe yeifels, keeping
their regulated courfe together.

CHAP.

44 The Construction op Timber

C H A P. VI.
Of the Blea.

ALTHOUGH the conftruftion of the Bark
and Rind in Trees be very much the fame,
there is not that refemblance between thefe and
the next coat underneath; the Blea. .This is
the part which fcparates the Bark from the
Wood, arid is- of a middle hardnefs between
them; much firmer than the Bark, but foftcr
and more juicy than the Wood. - > .

This may be feparated as the others, by
maceration : and^ indeed whoever propofes to
himfelf the pleafure of thefe refearches, fhould
ftejep a great number of Shoots of the feveral
kinds of Trees together, that where one fails
another may be at hand; and that difcovery
which is withheld in one may be unfolded in

another. -

Explained by the Microscope. 45

It is pofGble^ with a great deal of care, to
feparate thin pieces of the Blea from the grow-
ing Shoots of fome kinds of Trees, inr early
Spring ; but when this fucceeds the beft it can,
'tis ftill very much inferior to the other method.

It may not be amifs firfl to view the appear-
ance of the Blea in a tranfverie (edlion : we fee
that way the parts and their dilfpoiition y and
may trace them afterwards in their confl:ru(ftion.
If a piece of the Blea of common Willow bjB
viewed in this way, we fee that it confifts of oval
apertures, and a pale but intire interilitial matter.
'Tis plain the openings are not mere holes,
pierced in this intermediate fubitance; for we
fee they have thick fides. They feem the eflcn-
tial part of the whole ; the reft only a fbmething
filling up the interftitial fpaces between them, to
prefervc the Shoot in its form.

If we now place before the Microfcope a thin,
prepared, longitiidirial piece of the Blea of the
fame Willow, and apply a fomewhat larger power
than in the preceding view, we find thofe holes
were the apertures of vefTels lodged in that inter*
.3 mediate

46 The Comstrvction op TiMften

mediate fubftancct which is floccofe^ white, and
a mere mafs, without form. tXpon examining
the veflels carefully^ we ihall perceive that their
coats are cempof^d of this very floccofe fubftance^
only more compaAly put together ; and that the
reft, which feparates them, is nothing more than
loofe matter of the fame kindl thrown off froni
their jfides. The prepared Blea is moft ufeful in
diiclofing this ; for in frefh fragments the vefleh
and this fubftance feem all one common matter*

At Fig. 2. a piece of the prepared WillqW
Blea is (hewn as it appears before the Micro-*
(cope : a a^rt the veflels ; ^ ^ is the interftitial
matter.

The vefTels of the Blea appear dotted^ when
feen by lefs powerful glaffes ; but here we per-
ceive thofe dots are £> many oval fwellings, like
huds on a young branch ; but each fwelling has
as it were a mouth opening according to its
length. Thefe mouths are innumerable ; thejf
appear on every part oi the veffels, and fcrvc
the pijrpofe of keeping the whole in that con-
tinual ftate of moifture which is fo efTential to
the growth and encreafe of it. Fig. 2* r r.

^" -..

Explained by tbb Microscope. 47

He who would fee this well muft not (mly
make his preparations carefully, but Cut the
pieces in a fit feafon ; either juft before the firft
leaves of Spring, or in the Midfummer Shooting
time. Then we fee all the wonders of this
ftrudure ; the thoufands of mouths which open
throughout the courfe of thefe innumerable vef«
' iels, to pour their fluid into the interftitial mat-
ter } which fwelling with its quantity, like a
fpunge with water, preffes every part outveard
and upward into growth and thicknefs. It were
vain to feek them in the Winter Blca ; they are
fliut by its contraction ; and tho' a little water
keeps them in that flate at thefe times of « the
I year, the ocean could not at an ill feafon open
i them. * Even in freCh pieces of the Blea the very
form of thefe veflels is loft, as foon as their
juices leave them. Wherc-ever a piece is care-
fully and lightly torn off, the Microfcope (hews
ks vefTel j in their cylindric form at frril: ; and
[ fomething of their mouths is vifible in the more
perfect end of the piece ; but where they have
I been broken, and their juices let out, they col*
i lapfe, and nothing but a kind of flat white
I thread is diflingutihable. Fig. 3. a ^ c.
■ ^ The

4S The Cokstruction o? Timber .

The WIUow was felcftcd to flicw the ufe
thefc veflels have in the Vegetable Oeconomyi
becaufe in that light and loofe wood the mouths
arc veiy diftinguifhable : .but there are other
kinds in which the general conftruftion is more
evident : the Pear is one : in this ifirm wood the
veflels are much plainer, though their mouths
are lefs ; they differ alfo in colour from the inter-
mediate matter; for they are brownifli, while
that is pure white ; and being firm they are lefs
liable to contraAion.

I cannot tell whether fome eyes diftinguifh
better by the Microlpopc than others ; whether
the preciie focus is lefs eafily found by thofe
not fo much accuftomed to the Microfcope ; or
whether there be any other advantage which
that great nurfe of aptnefs, Pradtice, gives ; but
to whatever it be owing, I have found it very
difficult to (hew foinctimcs to others the things
inyfelf have feen moft clearly : and I have named
it in the prefcnt objeft becaufe it once afforded
a remarkable inflance*

The

*
I

m ^

Explained by the Microscope. 49

The Blea of the frefh Willow appeared f o a
Very careful obfervcr all one fubftahce ; the
mouths ill the veflels were feenj but not the diC^
tindlion of veffels and Flock. But a piece of the
frcfli Blea of Pear Tree then was placed in view,
and while we looked at iti the natural contradlion
from the evaporation and lofs of the fluid con-
tained in it> began ; and the floccofc matter
ihrank (o much fafter than the veffels could,
that though the ends had been ciit even at iirft,
they were foon fo altered that the veffels flood
out far beyond the Flocki and (hewed their form
and feparate nature mofl diflindtly.

In the Ozief, taken in its feafbn of quickefl
growth, in Spring, the Blea affords thefe veffels
yet more diflihdly even than the Willow 1 but
the matter is more difficultly managed ; for they
are fo tender, fo foft^ fo watery^ that *tis fcarce
poffible to keep them together. Fig. 5. fhews
a piece of it ; in which appears this farther dif-
covery thaa had been ihade beforci that the
mouths of the Blea veffels all open upwards*

D In

50 The CoNst&ucTioN of Timber'

In a piece ycc farther minified by a com-
bination of t*o of the moft powelfitl otgcft
glalTes* and with the advantage of a room con>
ftnifted purpofely for this fercice, a degree of
light was made to peiietrate the vety fubA&ncc
of thcfe ve£els. The fird appearance it ex-
hibited was that of many Cdls or Blebs, fiicfa as
we have fcen in the- Hark and Rind ; but on
more obfervatioii the appearance of tltefe Cells
was found to be neither eqatA nor regidar :
Nature has nothing to do whb fo wild con*
i^rufthxts as fcemed to ihew themfclTCS here :
the truth was at length diicovered : thefe ktttp-
ing divifions altered their places } and were
found only to be fma'.l portions of a watery Sap,
which the contraiflion of the part had preveftted
from efcaping with the reft, at the mouths of
the veiTcls, This appearance is pvtn at Fig. 6..
and may be a very necetfary lelTon s^ind hi^
' judgments.

A Vedel feparated from this Gzier fflea k-
fliGwn by itfcif at Fig. 7. 'Tis ftrange &at the
coat of veflels fo tender fhould be fo thick in-
proportion to their cavity j but this is the Icafl.
compadt of all Blea veiTcls.

chap;

tAINED iX THE MiCROSCoH. $1

'" * ■ ' "- -' ■ ' .-'''■

CHAP. VIL

Of the Wood*

AS we proceed into the more inward part
of the Shoot, in whatfoever Tree, the
conftrudioii becomes more difficult of ob-
servation : the parts are harder^ and lefs free
to ieparate one from the other; but with due
care, thefe macerations will afford, from one
kind of tree or other, pieces which will difclofe
their rnmofl: ftrufture. Many muft be examined
to find fuch ; "for it is not always in the Shoots
even of the fame fpecies thefe happy objcifts
inay be foutid ; the different forward nefs of th«J
feafon, the greater or lefs progrefs of the Sap,
and even the more or lefs healthy ftate of the
particular Tree, all afford variations, and render
\ the be ft fome times inferior to thofe naturally
much below thern.

D 2 The

52 The Construction of Timber

The common Pear Tree has afforded the
inftance from which the prefent views are given.
A piece of the wood of this tree, clean^ pure,
and perfedlly feparated from other fubftances, is
fhewn at Plate VIIL Figi i. nothing can be
fo fimple as its ftrufture : tho' difficult to ob-
tain,- there is little for obfervation in it when
we have it ; only that truth is always valuable :
and when we know the compofition of the wood
in one tree, we can underftand it in all.

The Wood then is fcarce any thing more than
an arrangement of plain and fimple tubes, re-
fembling the tubes of the Blea -, but that there
are no mouths in them; nor is there any of
the interftitial floccofe matter between them
more than what fills the very fmall vacancies
left by the roundnefs, between tube and tube :
nay, even that difappears as the wood grows
harder ; and finally, in fome trees, even the
tubes themfelves : their coats thickening both
on the outfide and within, *till neither cavity
nor interftice remains, but the whole is become
one firm fubftance.

This

•Explained by the Microscope. 53

This may be feen in a -tranfverfe view of the
common Oak 5 fuch being chofen as has grown
on ckyj for that from gravelly foils is tnuch
lefs compaft, lefe weighty, and of much lefs

ilrength and value.

In the Pear, and in moft: other Trees, fo much
of the vafcular appearance renaains in the Wood,
as always to make it eafy to underftand the ftruc-
ture : we always fee veflels, tho' with fmall
apertures, arranged in lines the one behind the
other, in many feries ; adhering firmly, and
leaving icarcc any interftices.

I When a piece of frcfli Blea is torn from a

I 5hoot, we have obferved that at the ragged end,
»'here the veflels have been broken off, they
lofe their form ; collapfing, and no longer ap-
pearing ainy thing more than flat threads: but
'tis not fo with the more firm and folid veflels
which compofe the Wood : they feparate indeed
in a piece torn thin, but they keep their form
I and roundnefs, and break all together ; not one
I by one 5 nor forming a kind of pyramid, as in
I the Blea J but an equal, even termination. A

D 3 piece

14 The Construction of Timber

piece of the frefli Wood in this view is given at
Plate VIII. Fig. a.

At Fig. 3* is the reprefentation of a piece of
the wood of the Bauhinia Aculeata^ whofe dif-
fcf ence appears very ftriking 5 but 'tis merely
that of greater and lefs : the veflels in this are
extremely fmall, very hard, and laid unufually
dofe together. The whole viewed with the
ufual powers of magnifying appears one com-
pad, uniform mafs j but greater glafles fhew
it formed juft as the others j only that there
is fo very Utttc of the interftitia! fobftance, that
even in the youngeft pieces the veflels fcem to
|ill the whole (paces, by fwelling into thein.

At Fig* 4. is reprefcntcd a tingle veflel of the
wood of the Pear, clean fcparated from the other
parts : this may be viewed all round, and thence
we are confirmed the wood veflels are mere cloft
canals, with no lateral apertures. The plain
and fimple hollow is alfo very well feen in thcfe
iingle veflels. Art would in vain attempt to
procure fuch : they are too fmall to be the obr
jeds either of the hands or eyes ; but there
never fail to offer fome of them among the

variety

Woo J}

Explained by the Miproscope. sS

vsiriety of macerations ; efpepi^Hy of fvich «s have
been rubbed about often with the hands.

At 5. fe a fcftion taken trinfverfely from the
bottom of Fig. 2 and at 6. a view of the like
kind from the Bauhinia^ Fig. 3. In the firfl
^we^ jfee a little remain of a fpungy fubftance
between the veflbls : at 6. there fcarce is any.

* p* ■■ I I

CHAP. VIIL

Of the Corona.

9^ I ^' I S ftrange that amcmg all who have
JL written 00 the conftruftion of Trees
Aud Plants, the Circle which furrounds the Pith,
;and feparatcs it from the Wood, altho* different
in a high degree from both, and of a com-
ipolition not at all refembling either, fliould yet
jbave had no notice, and no name. It is indeed

D 4 , the

56 The Construction op Tim^ber

the moft important part in the whole vegetable
fabric ; for 'tis from this alone propagation
and encreafe by Branch^s^ Buds^ and Shoots^

16 carried op*

• ...

It has been a cuftom to fuppofe the Pith of
Vegetables to be the part in which thefe won-
derful fources of increase refide ; but this theory
(brinks to nothing before a careful enquiry.
The ftate of the Pith in young Branches will
be (hewn in a fucceeding part of tjiis Treatife ;
and it will be found difcpntinuous from the
original Pith of the Trunk j and fo far from
proceeding from it before the other parts, that
it is in reality pofterior tp fome of them in the
time of its formation. This important office of
encreafe being given to the part to which it
belongs, we fhall fee that the Corona is in every
fenfe, both of conftrudtion and ufe, an objeft
very worthy of a careful examinationt

We have hitherto been employed about parts
of Plants which are perfe(3:ly uniform in their
conftruftion. Nothing can be more fimple than
the compofition of Wood 5 and if in the Ble^
and in the Rind there be a more elaborate

ilrudure.

Explained by the Microscope, 57

^rudure, dill it is the fame in all the Blea$
and in the Blea of all Trees. Here we have a
matter perfedlly different; the Corona is not
uniform, but confifts of a variety of parts : nor
IS their nature or their difpofition the fame in all
Trees. It is not ftrange this Circle (hould fo
differ from the others j for they form and con-
ftitute only one part of the Shoot ; but in this
lie the rudiments of the whole : and the
Branch which is to contain all thofe parts,
is to receive them only from this Circle*

The Corona then is a ring ufually more or

Jefs angulated in its out-line, placed between

the Wood and the Pith in all Vegetables. The

general Circle is cellular, compofed of Blebs and

veiTels, as the Bark and Rind, and is perfedly

of their nature ; only that at different diftances

are difpofed among it oblong clufters of different

veiTels. Thefe clufters are ufually eight or ten

in number; and give origin to the angles of the

Corona. They are not uniform or of one kind

of vefTels, as in thofe in the Bark, but each has

two diftin<ft forts ; the exterior ones anfwering

tp the Blea, and the interior to the Wood of

Trees : and within each of thefe are alfo dif-

pofed

58 The Construction of Timbeh .

;pored vefTels nct unlike thofe in the filea aad
Wood, and often even larger than they are
found in thofe parts in the Shoot.

Thus we (ee that each clufter of die Corona
is compofed of all the efTential parts of the fuc«>
cecding Branchy and that the intermediate pan^
of the cirde are abfolute Bark and Rind : they
are ready to follow and death the cktfter when
it goes off in the form of a Shoot ; becauie' it
will then need their covering and defence^ the*
in its prefent inclofed (late it does pot.

It IS from this conftrudticm th^ a Tpcje is ^
all times, and in all parts, ready to {hoot Qitf
Branches ; and every Branch in the facne xnan*-
ner to fend out others : for the whole Trunks
and the Branch in all its length, have this courfe
fof eight or ten cliifters of effential veffels ready
to be protruded out ; and the proper and natural
integuments as ready to cover tli^Q,

In fome trees thefe parts arc more evident,

^n others mor-e obfcurely arranged 5 but when

thpir nature is known, there is nonp in which

they may not be fouQd.

The

ISXPLAINEB BV TH£ MiCROSCOPE. 59

The Oak is ' not one of thofe treea in which
they are moft confpicuous and diflin^ ; yet will
the rooft curfory obfcrver perceive, in a tranf«-
verie fe^on of a Shoot of that tree^ that the
circle immediately furrounding the Pith is per^
fo^ly diftin(3:, both from the Pith which it
cnclofes; and from the Wood which furrounds
It. A fedtion of the Oak is given for this purr
pofe at Plate IX. Fig. i. and near it, at Fig. 2.
is placed a fediion of that tree, in which, of aH
that I have had the opportunity of examining,
this drcle is the moft diftind:. This is the
Parrot Wood of the Weft-Indies, the Bocconia
of Botanical writers. It fcems formed to lay
open this great myftery of Nature 5 for nothing
pan be fo palpable as the conftrudion : 'twere well
if this fpecies were always at hand in Europe ;
probably it will be foon ? in the mean time,
>he only Vegetable wherein the parts can be
fcen in a manner any thing refembling this, is
^n herbaceous Plant, the greater Celandine -, to
which indeed this Bocconia is in its Botanical

■

phara<5l:era, as well as in its inner ftradure, very
Tiearly allied.

6o The Construction of TnvfBEK

This tranfverfc fcAion of a Shoot of the
Bocconia is given at Plate IX. Fig. 2, With
what fupcrior beauty muft it appear from a frefli
Branch : for this was from' one brought from
Jamaica, and rendered manageable to the knife
by a long infufion in water. We fee here the
Rind a, with its Bark underneath, i; and, the
Vafa extcriora and interiora evidently mark'd in
them. Beneath thefc, at e, lies the Blea, pcr-
fedly diftingulftiable from them, but fcarce at
all from the Wood, f, the Branch being very-
young and tender. But even in this ftate the
part immediately within the Wood is moft pal-
pably diflinft: its fubftance, ftrufture, colour,
every thing, (hew that it is neither of the nature
of the Wood, nor of the Pith : equally unlike
both : and within this, but extending each way
beyond it, are thofe clufters of veflels which
we find in all Corona?, tho' lefs diftind : thefe
intrench upon the Pith one way, and upon the
Wood itfelf another ; being in their nature and
office of much more importance than both.
At /j is {hewn the fubftance of the Ring or
Circle, the inr^mediate matter of the Corona;
and at / / the cl Lifters of veflels which at their

egref^

Explained by the Microscope. 6i

egrefs from the tree are to form Branches :
thole the matter of the Corona always follows
out, in quantity enough to cloath them.

One Cliifter, feparated from the Ring, is
reprefented more enlarged at Fig. 3. In this
we palpably fee the fubftance of the Blea and
the Wood, and yet more evidently the veflels
of that latter part. At ^ the loofe and open
texture of the Blea cannot be miftaken by any
who are at all accuftotbed to thcfe obfervations :
at 6 the clofer ftrudlure of the wpod is perfedlly
difclofed : and at r a part of the fame wood
furrounding' the great vejflels ; but of a fofter
fubftance than the other, that it may not be
capable of prefTing thofe vefltls, on whofe free
courfe the growth of the whole Shoot, to arife
from this clufter, perfedlly depends. At d
the great veflels themfelves are (hewn, not
at all exaggerated by fancy, or the rage of
lyftem. It is juft fo they appear, and will
always appear ; even in the herbaceous Celan-
dine ; as well as in the arborefcent Parrot
Wood.

62 The Comstkuction of TimbeI

At Pig. 4« is given alfo an enlarged ricw of
the fubftance of die Corona ; in which, as in
all juft opinions, the greater power we employ
to examine! the more light is thrown upon the
fubjcd:. If it had been poiiible before to doubt
the nature of that circle ; under this advantage
of greater magnifying, it is not. The ftrudlure
of Rind and Bark are fb diftindt in it, diat an
accudomed eye would declare at once, that it
was a view of thoie two parts taken from {cmo
very good fubje£t which he had before him :
they would appear the abfolute Rind and Bark
of a Shoot, not their embryo's in the Corona*

On the Corona and its Clufters, (for in Nature
they are never feparated,) on this complex part
depends that incommunicable property of Vege-
tables, that they can be produced entire from
every piece. In animals, even where bounteous
Natarc. has given the wonderful advantage of a
re-produdion of parts, ftill it is but the part
which was loft that can be fo produced. The
leg of a crab being broken off, a new one grow^
in its place : but then it is only a leg. Nay^
everi in Spalanzani's great experiment of the jaw

-T _ ,_Jj —

CoBOX-^

ri 9

i i.

EXFLAIHED BY THE MiCROSCOPE. 63^

€>f tht Newt, when that part is cut away, *ti^
thtt part and no more that grows again : but m
Vegetables the whole arifes from a part ; and
that from every part cut off tranfvcrfelyr with
almoA equal eafe.

Tbefe Clutters follow the courfc of the other
portions of the Tree ; they arc therefore every
where : they are always capable of growing ; and
tfieir growth, even in a cutting of the fmallefl
twig, cannot produce a leaf or any other part
of X vegetable alone^. but muft afford the whole ^
for they are complete bodies, and the whole is
there, waiting only for the means of extenfion,.
fufikient nouriihment.

'Tis hence in all trees Shoots are thruft forward
fiom the Crowns and fides of Branches in Spring,
and after Midfummer, the feafons when the vef-
fels are moft filled; and hence that at all feafons,,
under fufficlent (helter and defence, Branches
rife from, naked cuttings, under the Gardener's
care. That they do not rife with equal eafe and
readine& from all kinds of trees is owing merely
to the difference of conftrudtion in thefe Cluftefs
ef the Corona. In thofe fpecies where that

fpungy

64 The Construction of TiMBEif

ipungy matter of the wood>\4^, 'Fig. 3. is very
loofc and open, the cuttings grow very freely t
in thofc where the fame fubftance is much morfc
compadl, and prefles more upon the veffels^ they

^ grow more difficultly ; and where it is very hard,
they will not in the common method grow at
all. It will be worth the practical Gardener's
while to attend to this : for, to raife fuch trees
from cuttings, there requires only to wound in
many places this interior woody fubftance, and
that way, to give the veflels frecdorh. He muft
not be exped:ed to ufe Microfcopes to find them
out, 'tis fufficieht that he be. told in general
where they are ; they lie deep, juft above the

' Pith : and when he would raife a Tree or Shrub
of the harder kinds frorri cuttings, he is only
to cut into the piece all round, as furgebns
fcarify. He will deftfoy many of the parts ; but
enough will remain to furnilh matter for fome
Shoots.

Scmething of this truth feems to have been
conceived by pradical Gardeners; fomeof whom
have recommended flitting, flafliing, or pricking
holes in the part of a cutting or flip to be
put into the ground. Others have decried the

practice ;

■■ ■ » . ■

-ih. fc

EiPtAiNEEi Or THE Microscope. 6^

ptiGtice ; dndi as thejr Tay^ from ill fuccefs upoii
the trial. Both may write truly : btlt they have
judged too generally on a fubje£l where the
matter dejiends upon the difFerdht (Irufture of
^particulars. He that cuts or pierces a fbft
^eeies, where the patt fufrdundiilg thefc vejflcls
is loofe and open ^ lets ih deftriidlion and rotten*
ilefs to the whole: but he who performs the
fame operation upon kinds where it is hard and
too compaft, gives courfe to thd natural powers
and miethdd of encrtafe/ If thefe kinds be
fcarifiedi and the others fecured by wax from
die too free ingrefs of the moifture of the earth,
few will Ml

7ir> "^

* -T

G tt A P. IX.

Of the Pittt.

1^j the cetiWr df ttvgry young Shoot of a Tr^
re&des the Pith : greater in Tome, and lefs
in others ; but prefent in aft. It is placed dofe
within the Corona ; the moiftening of whofe
cluders, and giving moderate and regulated way

E to

66 Thk Const ruction of Timbix

to their exten0o»» is it$ great ofSee: for the
thing itfelf, and its deflined ufes, have been mtT*
taken. It is fuppofed coeval with* or primordial
to all the other parts ; but it is indeed po(liiate»
and comes after ihem in the order of tiliic> as
well as in its ufes. It is nQ other ^um a celliilftr
fubilance, formed from the ini^er fiirface of the
Corona, when thc^growth of the clufters of
that part begins. We fee nothing of it in the
^orona itfelf» tho^ ever fo cartefuHy examined ;
for it does not exift in that part while dormant :
but as foon as a elofter leaves the circle» and its
parts ieparate for growthi this fpungy matter h
formed within them. Exhaled air. gives origin
to its Blebs, while the thicknefs of the juices^
cloathing the Bubble^ gives it form and fub-
fiance.

Thus is this interior fubftancc formed^ which
has been fuppofed primcevali and the great caufe
of produdion, of all the reft. Its office is re-
quired only while thefe clufters take their firft
growth, and it aifts np longer. The firft fesifi>n
is the time of its ^reat ufe, and it invnediat^ly
after begins tq decay.

Thus

Exi^LAJNEO BV THE MiCROISCOPEi 67

Thus we fee trees have parts of jitnited and
temporary ufe. The great vcflbk of the wood
perform their ofiice for feveral years ; t>tit it is
only V at particular ftstfed feaibns : in Spring and
at* Midfummer we find them in their duty^ full
oF their proper fluid i at other times vacant and
ina^ive: the Pith, in the fame manner^ lives
M%d ads for the firft year ; and (carce longer.

The ftrudure of the Pith has been as little
tinderftood as its office : figures have been pub«
H(hed of it» reprefenting it as formed in circles^
hexagons^ and polygons, with Aarry points, and
douUe linesi and ^n infinity more of various
configuration : yet the thing is bot one. To iee
it truly, we muft look where it is moft fimple.
The Walnut aflTords it in this cortdition. If we
fplit a Shoot of the con>mon Walnut, of the
growth of one feafon, directly down the mid-
diet we fee the central part divided acrofs into
(everal cells by thin meml»'anes, as in Flate X.
Fig. I. £• Each of thefe cells is oWong, fmalleft
at the ends, and larger in the middle, as Fig. i . a.
and examining the fmaller part we very diftinftly
fee tvfp membranes forming the twQ fides of

E 2 the

68 The Construction of Timber

ihc cell, and fcparate from the membranes of
the cells above and below, tho* they join the
one and the other in the middle b. Following
the coarfe of this furrounding membrane round
the whole of any one cell, we fee that cell in
its true nature : it is zt\ oval Bladder or Bleb,
of which this membrane forms the oval. Such

a one is reprefcnted alone at Fig. 3. The whole
of the Pith is the (ame with its parts ; therefore
the Pith of the Walnut confifts only of one range
of thefe bladders, fmaller at the edges, largeft
io the middle, and laid very exadly one upon
another. The Corona of the Shoot keeps them
in their place fideways : they have no weight,
fo they do not prcfs upon one. another down-
ward I and therefore they retain this form.

It is only in a very few trees that the Pith is of
this fimple conftrudion ; but having feen it thus
in one, we (hall iinderftand it in all. It is the
quality of the Corona to throw out blad-
ders of air, clofed in thin membranes ; they are
large in the Walnut, and therefore each reaches
acrofs the whole branch ; but in other trees they
are fmall ; and many of them muft be laid
horizontally together to extend from fide to

fide

Explained bV the Microscope. 69

fide of the Shoot. In the Dog-Rofc, rcprefented
at Fig, 5. we fee it takes ten or twelve circles
of the Pith Rlebs, to |ill the vacant middle of
the Branch : but Hill thefe Blebs are the fame
a« in the Walnut 5 only that here they are fmall
and round ; in that large and oval.

One of thefe Blebs, feparated from thofe
above, below, and on each fide of it, appears
4S at Fig. 6«

It will be obferved that at Fig. 5. where the
whole body of the Pith is rcprefented together,
the outline of every Bleb appears double ; and,
as it were, jointed in feveral places. This is one
of thofe wonders which have been reprefented
in elaborate engravings : but it is the mere
deception of the eye, viewing a thicknefs of
the* Pith in which a great many beds of the
Blebs are feen together, lying over one another.
There is no difference in the form of one Bleb
and another ; and we have feen at Fig 6. what
one Bleb is. Its membrane is fimple, and its
outline is fingle ; but here the outlines of many
Blebs are feen one over' another^ and variou(ly
intcrfcfting one the other.

E 3 It

^
/

70 The CoNSTittrcTioN of Timber

It has been the cttftom to view fuch a dice of

the Pith as could be cut ofF thin with a razor ;
but the moil careful way of executing this takes
in many courfes of thefe Blebs. In a flice cut
to one thoufandth part of an inch» fay the engine
here 6gured, a great part of this deception
vanilhes, becaufe very few beds of the Blebs
are taken : and in one of the fifteen hundredth
part of an inch» (for the inftrument will afford
fuch) the whole error vanifhcs. We fee the
thing as it is ; one fimpTe arrangement of cut
Blebs. Such a piece is reprefented at Ftg. y.

With refpc^ of thofe other figures fuppofed
to cxift in the Pith of Trees and Plants^ I have
fometimcs exemplified tbeir appearance by the
ftruiSlure of a piece of gau?je ; which, tho* com-
pofed only of ftratt lines, perpendicular and
horizontal; that is, forming fimple fquares;
yet if it be laid double, a new arrangement
of lines appears; and if again doubled, yet
another; and fo on, till, at fix times doubled,
the variety is in a manner endlefs. The dif-
ference of figures cannot be more between the
appcar^inccs of the . Pith of different trees, all

s made

jpjTjr

Explained iy the Microscope, yt

xxKide by iimple circles^ than in thefe which our-
felves have formed of fimple fquares.

Thus ends the examination of the ieveral
conftituent parts of Timber. Thefe arc all:
They are cffential; for thty are found in all
l&inds ; and they are here represented as they
have appeared, in repeated obfervationsy to the
Author I to his noble Patron; and to many
•affcmbtics of pliilofophic friends. Nothing is
enlargedi nothing altered from what the light
received in thofe fever-dl view3 : if in any part
he has been yet deceived, let it not be im-
puted {to purpofed mifreprefentation. Nothing
is feigned : and if in any thing he has erred ;
Reader! t^QXX an a man, and pardon human
frailty. '

E 4 BOOK

72 The GoN$TitircTioN op Timber

*»»ii^—i ^— — — — — i— ■— *— — *fci» ■ '■ ■■■■ ■■ fc

BOOK IL

Of the Vessels of Trees.

* •

e H A P. I.

Of the Vasa Propria Exteriora :
or, Thf Outer Range of peculiar
Vessels in Trees.

■ • *

THE VaiJi propria, or peculiar Vcflcls in
Trpes, arc pot pf the nature or ppndition
pf their copftituept parts, already dcfcribcd.
Thefe laft zrp efTential to the n^tpre pf a Tree,
as a Tree : t|ie others are acci<}eptal> ^nd belong
only to the fpecies* The Vegetable Strudture
pan exift^ without thefi? : but it cannot without
|he others. They contain the particular juices

Ex^LAINEB BY THE MiCROSGOPE. 73

pn wbich the virtues, qualities, and fpecific
properties of Trees depend. A Ttee can grow
and live» -and give fhade without them ; but
it cannot have eminent qualities. Thofe are
greateft where thefe Vafa propria are largeft
or mod; numerous : and where we (carce fe^
dieie^ we hardly tafle or fmell the other.

Of theie Veflels there are many ranges dii^
pofed ii^ Qr between the feveral parts: their
£tuation coul^d not be underftood from defcrip-
tion, until thofe parts were particularly known i
but now they will he traced with eafe.

Of the Vai^ propria there are four kinds ;
and of thefe each h^s its allotted place, its
peculiar fcmn, its different ftru^ture, and its
feparate ufe. Some trees have them io all their
parts } others in fbme of them ; and there are
which ihew them not at all Where they arc
not difcernible by the eye, reference is to be
had to the tafle ; for if there be nothing perr
. ceived by that, where none appear to the fight,
it may bp reafonable to give oyer the fearch,
and conclude there are none.

74 The Constkuctioji ow Timkik

To follow the order of their attm^aamt in
the Tree, their kinds are d)e£b t u The Yafii
cxteriora, lodged between the Rind ttd the &rk*

2. The Vafii interiortt fitotted in the Bark.

3. The Vtft intima» kx^ed in the Bles.

4. The Vafii peculiariai in the Corona. Btfide
thefct there are the Sap Veflels in the Wood ;
but they are common to all Trees.

. The firft of thefe, the Va£i propria ezterionlb
have been ihewji in their place and fcopoiiion,
at Fig. 3. where they appear as roand dariu
coloured bodies, lodged between the Rind a^
and the Bark 6, and entrenching upon ihe iub*
ilancc of both,, making their own beds half
within the Bark, and half within lk^ Rnd.

To know their ftm&ore we miift care&Hj
feparaee the outer Rind from die inner fiark ;
and this may be done, with ibtne acten^m, in
a Isf ing Branch, jnft at the time cf ks fwelliag
for die Spring, or for the MidAmsmer 9x>ot 1
but much eafier by the means of maeeratiocip

When

EXPLAIKED lY THE MiCROSCOJf E. 7 J

When the Rind is peife^ feptrated diat
way, it leaves the Vafa propria of this chtt
behind it : they fcarce adhere to the inner Bark ;
not at all to the Rind j end therefore lie imdif-
turbed ypon the piece thus ftripped. We hit
them as reprefented in Plate XI. at Fig. i . diey
ftf e diipofed in little pad^ts, like cordsi^ and do
tiot nm ftrait down the Branch ; but i&tct^
;^Ting with tnc tnocher, form a very pr«Ry
kind of net.

When we raafe any one or more of thefc
packets of V^ek» we perceive that it here and
there fticks a little to the fubftance of the Bark,
iHit no where to the other veflels : they put
very freely where they pafs over one another^
and will indeed fall afunder in thofe places^
if they be clipped fhort^ and ihook about, in
a paper.

When we examine a thin tranfvcrfc jf»ece of
one of thefe packets^ we perceive that it is
compofed of twelve or fifteen di(lin(ft veflels,
whofe Rinds feeni hard, and oinft indeed be fo ;
for they preferve their roundnefs notwithflanding

their

76 The Constructiom of Timber

their mutual prefllire of one another, and th&
prefTure alio of the Rind and Bark. A view of
fuch a piece is given at Fig. 2.

Laying feveral longer pieces of thefe packets
before the Microfcope/ ve (hall, v^itb a great
power, find fome happy fi^gment in which we
may fee the caufe and nature of the adhefion of
thefe parts to the Bark. Such a view is given

flt Fig* 3* ^^ ^cc ^^ 01^^ ^^^ ^^ veffels of the
packet a little ieparated, and in the parts a a a
we perceive upon the fides oval deprefQons,
dotted as it were with pin holes; thefe are
tnofl probably a kind of glands, which feparate»
from that general ftore of Sap with which the
Bark is filled, the peculiar juices which are found
in thcfc veffels.

A great deal of patience, a vaft number of
plgcfts, a good Microfcope, and a fair day are
requjfite for viewing the Vafa exteriora, for this
purpofe; but he who^takes all thefe precautions
veill not be difappointed.

If fpme of thefe packets be worked about
yf\fh gcntlcnefs, the open ends will give an

opportunity

Pl.ll,

YAS^ mOPSIA EXlTISIiXOR^

»f

Explained by the Microscope. 77

opportunity of getting fbme veiTels feparate and
imgle. Thefe being put into fpirit of turpen*
tine, will, after a week's (landing, become very
tranfparent: and one of them, viewed with a
great power, appears as at Fig. 4. divided in a
very wonderful manner tranfverfely into cells :
thefe are fliort, ovali and terminated by hollow
valves ; and ufualty, fbme of them being full,
and others empty, the conftrudion is very pret-
tily ftiewn. We iee at ^ ^ fome parts of thofe
pin hole glands ; and it is fingular they always
have their origin at the bafe of a cell longer
than the others. The brownnefs of the con-
creted juice in the Oak, from which all theie
obfervations are taken, renders the cells which
are filled very diflinguiihable : but there are
other vefTels, with colours more diftinguifhable
ilili^ to be mentioned in the fucceedirig chapters*

r^:

C H A ?•

78 The Construction at Timber

CHAP. IL

Of the Vasa Propaia Interiora#

THESE are Vefiels general^ of mor« im-
portance than the preceding ; and often
of more dian any other part of the Tree*
They are, in fuch kind$ as are renowned for
medicinal virtues, ufually large : th^ carry the
milk juices in the Sumach; and the greateft
quantity of the turpentine^ as alfo the fineft and
higheft flavoured, is lodged in them,, in all the
kmds of Pine. Their iituation is (hewn in the
Oak in Plate III. at letter d; hut tho' they are
of no moderate fize in that Tree, they are yet
much larger in the Pines ; we fhould therefore
fclcft a Tree of that genus for the tracing them
in the prefent inftanecc, liF there were no other
caufe of preference : but *tis our bufinefs to fee

them

_ £

ExrtAlM£D BY THB MxCRO&COP£. 7^

tbeia ae cleti: and free from their juices at pof-
iible» in Order to onderfland their ftru£litfe^
and happily the juice which filb theixi in the
Pines^ being a pure turpentine^ is Capable of a
perfect fohitictfi ki fpirit of 'wine.

The ^ecies of Pine in which thcfe Veflcls
^ffe &en moft of all diftindly, is the Pinus
OrientaHs of die Botanical Writers. They are .
vaft apertures in every kind of Pine. If we view
&em juft cut wc fee bubbles of a yellow tur-
pentine riling out of them. If a thin traniverfei
fiice ia laid before the Micro£:ope» aft^r foaking
H in ^irit of winp> they ^pear as great oval
holes, into which ftraw; m^ht be thruft with**
out doing them violence. Such a ie£tion of the
Oriental Pi&e is given at Plate XII. Fig. i.
where we iee a chain of thefe Vaft apertures
regulaiiy placed in the fubftance c^ the inner
Rindf and conforming themfelves to the ibape
of the Branch.

it cuiDot but be obferved^ even 1^ the leaft
curious, ^at the outline of the(e vefiela is com^
po&d of a. Ring of oval apertures, b : thefe are
in reality the mouths of other veiTels ; and the

refult

So f HE CoNiTRUCt lOlf OF TlH BfiR

refult of the obAfvatioii is, that the very coafi
of thelb veiTels are tbemfclves vaicular. A vieW
of an arrangement of thefe vefleb, as they ap-
pear in H tranfverfe Slice cut from one of the
Vafa propria of this * Pine, is given at Fig. Zi
They appear, by the ftrifteft enquiry I
have been able to make, to be of the fame
nature with thofe which conftitute the Packetsr
in the Vafa propria exteriora } fo that if we
conceive one of thofe Packets opened in its
center, and the veffdt driven every way out-
ward till they are ftopped by the fubftance of
the Bark, they will give us an idea of thtf
flrudure of the Vas interior, which is no morti
than a great cylindric hollow formed in the cen-
ter of fuch a Packet* A view of fuch a vefleU
as taken out of the Pine, is given ft Fig. 3.
and at Fig. 4.. is repreiented their exadl: dif-
poiition inva fomewhat older Branch, where the
hardening of the parts has driven them clofer
together 5 and where they appear as in the hol-
low of fuch a piece; the Wood Blea, and even
part of the Bark, being pulled away. Few Trees
afford more beautiful obje<3:s than a piece like
this, of the Pine, before the Micrbfcope here
defcribed, ufed in the oblique manner.

From

TCiSA. PROFBIA- Jl^TXBXOtUa.

It. a.

... /

1 « »

• 1 « • i

< > • k I

^ l_^«.5

Explained by ^hb Microscope. 8i

From what we have feeri of the conftrudlion
>nd ufc of the Vafa cxteriora, the nature of the
pUrpoies thefe anfwei: iii the Vegetable OeConomy
is not hard to trace. If^ as is mod probable,
the vcffels of the coats of thefe, are the fame
with thofe, they are filled with the eflcntial
juices of the kihd ; slnd frdih thoie cells 'tis
probable that they difcharge the matter they
contain into thefe great receptacles, thro' aper-
ture& in that part of their furface which forms
the infide of thefe vefTels : but this is no more

than opinion. Conjedhire muft be carefully dif-
,tingui(hed from obfervation; and it mufl be
owned it may err here : for thefe veffels arc
fo fmaU, and ib difficult to be got at, that I have
never been able to fee either thefe openings, or
tiieir contends. Btit whether it be by thefe bi:
by any other means the Vafa interiora are fup-
plied, their office is certain ; they hold a rich
juice, fecrcted from the nourifhment of the
plant, perfeftly feparate from all the other fluids :
and from their fituation in the outer Bark, it is.
evident whence it happens that in this part we
find the virtues and t^e flavours of Vegetables
nioft refide.

P CHAP.

82 The CoNsntiycTioN of Timber

CHAP. nr.

Of the Vasa Propria iNTiMiS^

NOiwithftanding that there art in the cow-
ftrudfeion of a piece of TinAer twor
arrangements of Velfels within thefe IntimalK
namely, the great Sap Vcflfels of the Wood, aiA
thde of the Corona ; yet as the fontrer are not (^
the nature of Vaia propria, (not carrying any
peculiar juices^ but only Sap^ whtcli is nearly
the fame in dll Trees) and as the others are not
of one kind/ but a mixture ^i (eireral; and
indeed are only repetitions in miniature of thefe^
and the preceding ; the Reader will net di^tr
&e name Intima to the prefent.

% T%

EtPiAlUtD ir THt MiCROSCOFf .• Sj

They arc large, confpicuous, and very in*-*
portant vefTels : their natural place is ia the
Blea ; the part of a Tree which lies between
the Bark and the Wood : they arc never feeii
in any plaf:e exterior to this^ but foQietimei
they are repeated in the very fubftance of th<;
Wood I nay^ and in the Corona itfelf ; in fooie
degree difplacing and intercepting the othef
parts.

It is veiy eflential to fee thefe in a Tree
where they are moii confpicuous : for theif
being thus intermingled among 6ther partsy
renders them in many inftances obfcure : at
kaft the b^ obferver will be a£ble to find thefioi
e&vtch the more readily in other kinds; from
fejivitig ontie feen them where they are thus
bbvious. Their coats are thicker than tjiofc
6f any other veflels 3 but in ibme kinds the/
htye alio a colour in their contents that renders
iSl dotabt eoooerning *them impofiible.

The Tr^e in which they appear nioft palpabjld
of ajl, is the Pifcidia JErythrina. In this they
iiave ft fcarlet colour, never to be overlooked :

F 2 and

^4 The Constritction of Timbei(

and it happens that the other parts lie fo coil«
ipcudus and fo regularly about them, that thei
muft be known every where, for ever, by ai^
one who has once feen them here. A view o^
a tranfverfe feition, from the Shoot of this Tr
is given at Plate XIII. Fig. i. In this the V;
propria interiora {a) hold a diftinguifhed place
and jufl within their circle lie the intimaj

large, fmgle, confpicuous, (fee the letter 6) di&

* .i

pofed in a manner perfedtly fingular : certaiilj
aflemblages of them, about three in number^
following their exaft courfe in the Blca, but
alternately arranged in lines and triangles. Bc-|
fides thefe there appears here and there one (£\
them loofe and unarranged among the Sap Vcf-i
fcls of the Wood, as at c. And in the Coronji
there is fcen at d a perfeA circle of them, ia\
the fame alternate arrangement of lines and

triangles*

The Reader will be pleafed to obferve, that

in this and all the other figures of fedkiens given

in this part of the Work, the Veffels and othci

parts intended to be particularly fhewn are the

only finifhed parts. The conftrudion of the reft

is thrown in faintly, that the eye may not be

confufecL

Explained by the Microscope* 85

confufed. There is more in the Pifcidia worthy
of note befide thefe Vafa intima ; and it will be
figured again with that view hereafter.

The exadt fituation of the Vafa intima in this
Tree is always fubfervient to that of the Vafa
interiora : thofe are placed near the. inner edge
of the Bark, and the intima keep a nearly exa<9:
dijftance between them and, the Wood ; three of
them appear to accompany one, of the interiora,
as in Fig. z^

It is not at all diflkult, after a fuccefsful

maceration, to feparate fome of thefe vefTels from

the Blea : in that flate they appear perfedt

cylinders, with thick, white coats^ filled with a

hard 'red juice : and, fo far as I have been able

to jfe6, perfedlly uniform on their furface. Some
of them, thus feparated, are fhewn at Fig. 3.
It is thus alone we can view them by the com-
mon powers and apparatus of Microfcopes ;
btit 'tis not thus they are feen in their greateft
bcauty-^To obtain that, a piece of a young
Branch of the Pifcidia is to be cut into fhort
cylinders ^ one of thefe is to be fplit 5 and after

F 3 juft

86, The Gohsthuction of Timbisr

jufl fo Much maceration as will loofea the partf
Ohe frprn another, the Wood is to be got away.
This is beft done by means of a fmall hollow
phifTel^ (haped like the half of a quill. The
opening is to be made with this, and then the
Wood pulled away with a pair of fine pincers.
The part where the chiffel pafled is to be cut
off and thrown away, and th^ feft preferved for
pbfervation. Many pieces (hould be treated in
this way, and chiflcls of many fi^es ufed for this
purpofc 5 for 'tis only by that variety, and
among a number of pieces, that one or two cai) i
be found happily cleared of the interior part,!
One of thefe pieces, fuccefsfuUy cut* is repre*!
fented at Fig, 4. And befide the Vafa ihteriars^
jvhich make a very pretty appearance in (udi
an objeift, we fee thefe intim^ in every view w?
jcould wilh : upon t\vt top of the fetSion we fee
^heir whiltis mouths filled with , a crimibii con
pretfed juice 5 and upon the fplit fides we fcartt
^ver fail to fee feveral of them in their whdc
length i for their coats are fo ftrong, that they
very tfeldofti tear ; bu|t ufiially ftand oui> in thcif
bkces*

Til?

TdS^ FEOmXAHrTZMuA.

•C"-^.

EXPIAIJKED BY THE MiCROSCOPl. 87

The coat of the Vas intimum has nothing of

that vafcular ftrudture of that of the interiust

it feems one firm, folid, uniform, woody fub*

^ fiance, formed to keep the precious juice it

contains in perfedt fecurity. It muAf not be

omitted here, that this juice, in the preient

inflance, is of a fubftance fo compad: when

dry, and is fo firmly united every way to the

iides of its veiTeh, that preparations once made

of the parts will never Ipfe their chara<3:er.

If a tranfverfe feiSion be cut of only the thou--

fandth part of an inch in thicknefs, and be

immediately plunged in Ipirit of wine, the

Veffels, when the whole is viewed in a few

drops of the fame fpirit, appear as fo many

rubies : and fo firmly does their contained juice

keep its place,- as well as colour, that many

years fteeping in the fame fpirit does not diflblve,

or fcparate it^ I would not venture to relate

fo ftrange a thing, but that I have niany Slices

now in fpirit which are unaltered in fix years

keeping. The matter of colour is fo important

in this objeA, that a fecond Figure is given

with that advantage. What this indifibluble

juice isj (for neither does water afiedt it other*-

F 4 wife

88 The Construction of Timber

wife than by dcftroying the parts in which it i«
lodged) or what may be its qualities, is a thing
very worthy of trial. How great is the dif-
ference between this' and the Turpentine of the
Vafa interiora, which the fame ipirit plears
away with the greateil eaf? !

CHAP. IV.

Of the Sap Vessels.

T cannot but have been phfervedt that in
our Hid Plate, where all the parts of a Tree
are ihewn together, the moft numerous, ^$ well
as the largeft apertures, are in the Wood. All
apertures feen by this view are the ends of
veflels cut thro' by the iriftrument ; and the fizc
and number of thefe command the^firft attention.
They are in no Tree larger than in the Scarlet
pak of America. We have feen the appearance

Explained by the Microscope. 89

0f a thin Slice in that Plate ; but it will be
proper to give here ah idea of their diipofition
In a fplit truncheon of the fame Tree ; fuch as
the ibrmer. If a fhprt cylinder of a three years
Branch of this Oak, a little macerated, be hol^
lowed away with a chiiTel fo far as to take oat
the Pith and the Corona, it appears as at Plate
XIV. Fig. I. The Blea and Bark are there
alio pufhed away, fb that the Wood form$
almoft the whole of the cylinder; and it is
wonderful to obferve how large a portion of
It is occupied by thefe large apertures.

On the fides of the Iplit piece we fee thefcf
Veffels very confpicuous ; for they are very
thick : and it is not difficult, with fbme care
and attention, to loofen feveral of them.

If a number of thefe, thus feparated,' be put .
into a vial of rain water, and frequently (hook
for feveral days, fome will at length be found
perfed:ly clean. Thefe are to be then put into -
Ipirit of wine ; and when that has been two or
three times changed, they will be in a condition
to be viewed for underftanding tl^ir ftrufturc.

Some

90 The Construction of Timber

Some of thcfe arc reprcfcnted, as they appear
to a great power of the Microfcope, at Fig. 2^
where, / not withftanding all' the violence that
has been offered them, there will ftill be fcen
in many of them the remains of valves ; by
which doubtlefs thefe Veflels in a ftate of nature
arc divided into many cells.

Jn the Willow-leaved Oak thefe Vcflcls, tho*
ibmewhat fmaller, are firmer and more com*
pa£i than in the Scarlet kind ; and, having
thicker coats, are fitter for examination. In
the Veflels of the Scarlet Oak nothing could

be feen under the name of a coat but a mere
membrane, refembling a piece of thin parch-
ment* In thefe, as reprefented at Fig. 3. th^
coat is a palpable ring, in which traces of lines
furrounding one another may be feen ; by
which 'tis not difficult to underdand, that it
is compofed of feveral men^branes covering one
another. It has happened in feme pieces of
thefe Veflels, long (hook about in water, that
the out^r membrane has feparated itfelf like the
huli of aa almond in blanching ; and in this
^ate we not only fee that there is fuch a mem*

branCi

EXPLAINKP BY THE MiCROSGQFE. gt

brune, or probably a number of fuch mem-
branes^ but alfo that they are vafcular^ as
^t Fig, 4.

A fplit and hollowed piece of the Willow Oak
|s reprefented at Fig^ 5. in which the thick
coats of thefe Vcflels render them very con^

fpiCUQUS.

Thefe Veflels, which are, in nature, ciftern$
pf Sap for the feeding the growth of the whole
Tree ; and from which it bleeds fo freely in
the Spring and at Midfummer; are fo large
that they are capable of being filled with
coloured wax, in the manner of the veilels in
anatomical injeiflions y and this way they afford
fo pleafing objefts for the Microfcope, and give
fuch excellent opportunities of tracing their
(courfe and ftrufture, that it would be invidious
to conceal the method from the curious Reader.

A view of pieces of the Oak, thus treated,
and of the efFedl it has upon thdir Vcffels,
is given in the additional Plate XIV*

The

92 The Construction of Timber

. • «^ ■

The method.of. filling the Vcffels is this :

A great many Shoots of the Scarlet and other
Oaks arc to be taken ofF in Spring -, they muft
be cut into pieces of about two inches length,
and immediately from the cutting they mufl:
drop into fomei warm rain water : in this they
arc to ftand four and twenty hours j and then
be boiled a little. When taken out they are to
be tied on firings, and hung up in a place where
the air pafies freely, but the fun does not fhine^
When they are perfeftly dry, a large quantity
of green wax, fuch as is ufed for the feals of
law deeds, is to be gently melted in lain earthen
pipkin fet in water, the water to be heated and
kept boiling. As foon as the wax runs, the
Sticks are to be put in ; and they are frequently
to be ftirred about. They muft be kept in this
Aate about an hour, and then the pipkin is to
be taken out of the water^ and fet upon a naked
fire ; where it is to be kept, with the W2(jx boil-
ing, for two or three hours j frefli fupplies of
the fame green wax being added from time
to time.

After

f|tt^S

Xip Vesselz,s

rL-i^-

'•

— - — AZTE-r^

, EXPLAIfJED BY TH£ MlCRO^COPlfc. 93

After this it is to be removed from the fire,
and the Sticks immediately taken put with a pair
of nippers 3 when they are cold^ the rough wax
about them is to be broken ofF» Both ends of
each Stick are to be cut oflF half an inch long,
and thrown away ; and the middle pieces j&ved.
Thefe are then to be cut into fmaller lengths,
fmoothed at the ends with a fine chifiel> and
many of them fplit in various thicknefiles.

Thus are obtained preparations, not only of
great ufe, but of a wonderful beauty. Many Trees'
this way afford handfbme objeds as well as the
Oak I and in fbme, where the 3^p Vefifels are
few, large; and diftindr, the (plit pieces refemble
ftriped fatins, in a way fcarce to be credited.
It is in fuch that the outer coats of thefe
Veflels are moft happily of all to be examined*

CHAP.

94 Tu* CoiMTftoc'rioN op TimbeiI

m^-^mmtmmmmmmmmmtmmm^m^m^kAmi^

C H A P. V.

Of the Vessels of the CoRONii.

W£ have fetia what are the differences of
YcSkh in the Vegetable Stru^ure ; for
«re luvt already viewed all their kinds. Tb«(
CotQUSL h the whole in miniature : it contain*
the embryo's of future Shoots; and therefor^
fiittft cofitaJo their YefTeki and can coioftain no
otben'

We have feeii that of the two ^arts whereof
the Cofbna confifts^ the Ring, and the Clufters,-
the Ring i3 the faiJie with the Bark ; it there*
^Ore h^ the like Veffels. Their appearance
indeed is only that of the fame objeds viewed
with a lefs power ; only in one point there is i

inanifeHt

Explained KY the MiCRoscoPfi. 95

manifeft diAinflion. This is in thofe openings
which a great magnifying power difeovers in
thefe Vcffels. Thefe are proportionably twice
as big in the Bark Veffels of the Corona, as in
thofe of the grown Branches : nor i^ it difficulty
from what has been faid of their ufe, to guei^
the rcafoii. Thefe Vcflels arc reprefented at
Plate XV. Fig. 1.

As the Veffeb of the Circle or Ring of the

Corona diflfcr in nothing cffential from thofe of

the Bark ; neither do the Veflcls of the Cluftera

diiffer more from thofe of the fcveral parts of the

groNvn Tree, of which they are the embryo's*^

(t is often po^ble (I cannot indeed fay it »

always eafy) to diftinguiih the Vafa intima iii

the outer and inner ends of each Clufter ; among

the Veffels of the Blca. They, as wdl as the^

Blea VefTels, are very difficultly viewed with any

diflindtnefs in rfiis compadt and crowded con-

^ dition ; wherein they ftand in the Clufler : but

what difierence I have been able to fee, in thefe

fcflerBleaVefels, is, that they havefewer but largef

mouths than thofe in the Blea of grown Shoots; ;

and that there is an utter want of the fpungy

. interflitial matter whicji in that flate keeps thenr

feparate

96 The CoNstRuctioii of Timbe*

feparatc and at a diftance. That the Vafa intim^*
the proper objed of enquiry here» have thinner
coats, and are not fo perfedly cylindric*

In the central part of every Clufter we muft
cxpedt to find thofe vafl: Sap VefTels which feed
the whole interior part of the Tree ^ nor are
we difappointed : they are indeed yet larger in
proportion here than we find them in the grown
Branches ; for 'tis here they have their greatefl
ufe : 'tis thefe alone that can fupply the Shoot
in its firfl pufhing out from the Branch. It is
to grow before it has communication with the
outer air; and 'tis by thefe Veffels,, which here
are always full, tho' in other parts they are fo
only at particular feafons, that the growth of an
angle of the Corona is to be fupported and
fupplied in its egrefs into a Branch.

BOOK

i •

T^SSmU^S OFTBE COXLON-.^ ^'^■'S;

'/ C^y7fn.w

■ ^'a^a/ /cn^niw or- Bie^ drrtrTza^

t^aJv 7/^fe//^ of fn£^ Carrn^.

IL. ,_» i _A. .-

Explained by the Microscope;. . 97

lit t iV

' * m

6 o o ic

III.

Of the Encrease by Growth.

CHAP. L

Of the (jRowf H of Branches.

TO kriow the parts of the Vegetable Con-
ftrudion, unlefs we have alfo from that
knowledge learned fomething of their ufes, were
a vain and idle boaft. The encreafe of the Tree^
the new and multiplied life that it receives from
the growth of Branches^ each capable of be*
coming an entire and feparate Tree by only
flicking it in, the ground; is^a matter of the
iirft moment* The csconomy and encreafe lie

G here;

gB The CossTAtJCTioN w Timbeh

here ; and thcufes of men are fapplied as well
thus, as from feeds } and with the advantage of
more expedition.

Since it is from an angle or part of the
Corona the Branch naturally arifes^ 'tis in this
place we may mod naturally and ufefuUy trace
it. . Thens have bden miftakes about the nature
and method of the growth of parts in Plants,
as well as in relation to thofe parts themfelves :
but *tis not the purpofe here to point out the
errors of others, but plainly to enquire the way
to truth. It J\as been thought, nay it has been
affirmed under the fandlion of very reputable
2iame.s^ that the Pith is the firfl part ip all
growth, and that the others form themfelves
about to cloath it. Experiments have (hewn
*lis otherwife j ahd the way to certainty in thi*
enquiry k fo |>lkin, th^ 'tis impoilible any one
di(pofed to obfervation can miftake it.

The Pith is fb far from being the original <»*

firft fornied part, fo far from giving origin to

»i • ■

the reft, that they are always formed or pu&ed
forth virithout it. The Pith begins to ^^w
after the Branch .ha« ihot to fome ie»gih, asd

ceafes

u^-l.

Explained BY THfe Mickostopi. gg

chafes to be of ufc after a few months : hay in
the end lofes again its accidental beidg^ the
Branch ribmaining per&dly ibund and healthy
without it.

Any Clufter in any pirt of the Corona^ pro-
truding itfelf onward and outward in the grow^
ing feiafon, carries a part of the Gircld out with
it. This protruiion is naturally made in the
bofbm of a leaf, becaufe the Bark and other
parts are there wejaker and moiftei". The Clufter
itfelf is a perfeft piece of the Wood and Blea } and
the Bark which follows it out in its progreis, per^
fedly cloaths it. Thus is the firft protruiion c£
the Shoot made : but all this while there is no
Pith. There was none origkiklly in the Clufter di
the Corona^ and all things yet appear unaltered in
it ; only for their covering. . The continuatbn
of growth is made by the extenfion of all thd
parts obliquely upwards y in the courfe of this
extenfion they hollow themfelves into a kincl
of cylinder, the form of the future Branch :
and by this diipofition a fmall vacancy is made
in their center. This enlarges as they cncreafe %
and as it enlarges it becomes filled by the
exfudation of thofe little bladders before-men*

. G 2 . tloned;

loo The CoNstRUCTioN of Timber

tloried ; which remain and conAitute the Pith f
fed from the inner coat of the wood, which
already begins to form itfelf into a new Corona;
by its elafticity prefcrving, and enlarging that
cavity it fills.

To follow this enquiry fuccefsfully, fplit a
young Shoot of the Red Dog-Wood, or of the
common Dog- Wood of pur hedges^ early ia
Spring. If the fiifure be continued diredly
thro' the two oppofite Buds in any part, there
will be feen an angle of the Corona forcing
itfelf out on each fide, in order to make a pair
of oppofite Branches. Each protruding angle
forces its way thro' the foft young Wood, not
by tearing its VefTcls, but gradually infinuating
itfelf between them ; and nothing can be plainer
than that it is an entire Clufler which is thus
thrufl forward to become a Branch ; and that it
leaves a thick line of the Circle or Ring of the
Corona behind it. This is very happily vifible
in the Red Dog- Wood of America 5 becaufe the
Circle of the Corona is at that fcafon very green,
and perfeftly diflinguifhed from the Wood,
which is of a whitifh hue, and from the Pith,
which is of a pale brown. The Bud, pufhing

onward.

Explained by the Microscope, ioi

onwari}^ leaves a kind of vacancy behind it^ or
between its afcending bafe and the' line of the
Corona : thro' this vacant fpace pafs a multitude
of yeflels, which fupply the afcending Bud with
a great deal of nourifhment from the line of the
Corona, which is left behind it.

Here feems the great ufe of this line of the
Corona in the cecoriomy of Nature : and in the
path of knowledge it ferves to eftablifli, beyond
doubt, the True Hiftory of the formation of -

that fuppofed original part, the Pith. The

Clufter of the Corona, which is to be a Branch,
communicates with every part of the parent
Tree j except its Pith ; but all communication
with that is flopped by this circle : nor- can ^
there be any intefcourfe of juices between their
Veffels and its Blebs. We fee in the examination
of the Clufter that it has no Pith of its own :
we fee by this line of the Corona it Can have no
communication with the Pith of the Tree ; and
'tis not only impoffible that this Angular fub-
ftance (hould pierce that Ring, and enter the
Clufter, but our eyes fhew a fpace, a vacancy,
between them : a part of the Shoot, wherein
there is no Pith ; and in its place a courfe of

G 3 Sap-

102 The CoNSTRUCTfoN OF Timber

Sap-Vcflcis; things perfectly diftlhdk from it,
in natu|tr, form« and difpofiiion. This fpace^
tho- it be proportionably greateft in the very
young Bud^ yet it remains long vifible after the
Branch is grown ; nay, and in fome kinds,
does at kngth obtain a kind of coarfe Pith
for itfclf.

At Plate Xy I. Fig, i. is (hf wn a piecp of
9, youpg Shoot of Dog- Wood, fplit thro' the
two oppofite Buds, to (hew their nature. The
part a is the, remaining line of the Corona;
6 is the fpace left by the afcending Bud ; and c
ftre the Veflcls pervading it.

If now we talce a fhickpr piece of the fame
Shriib, and inftcad of fplitting it thro* two Buds
we carry the knife thro' the (lumps of two
Branches, formed by twQ fuch Puds in fome
preceding feafon, we find the veftiges of every
part remain. Such a piece is rppreftnted af
Plate XVI. Fig. 2. Here we fee the line of
the Corona (letter a;) ftill remain, but not Hip-
plied with any new Clufter : sind hence we may
learn that a fecond Branch can never rife from
|he fame ipot, altho' thp firft fliould perifli by any

accident.

Growth of£jl^

-J^

Explained by the Microscope, 103

accident. At b the fpace ftill remains j and its
Veffels c run thro' it r but as we carry our eye
along the afcending Shoot, we fee at ^ a Pith in
jail refpedts the fame with that in the center of
the parent Branch. This Pith of the Shoot is
not continued from the Pith of the Branch,
as has been fuppofed ; for they are not, nor evc^
were, continuous : there is, there always has
beea from the beginning, a fpace between them :
the fpace exifted even before the Pith of the
Shoot was formed. This Pith therefore was
neither derived from the parent Tree, nor
original in the Shoot ; tut is a mere temporary
and periftiable production, exfudated from the
Shoot itfelf, and deftined to ferve ' its prefent
purpofes, and then to perifli.

Let not the newnefs of this opinion makg
any one paufe to^recpive it! Had we never had
new opinions, old errors would have been im-
mortal : but happily here we may refer not only
to the Reafon, but the Eyes ! The fhrub is before
every one ; a pen-knife makes the divifion ; apd
fcarce a conamon rcading-glafs is neceflary to
ebferve i^

G 4 Altho*

104 The Construction of Timber

Altho' in this Shrub the vacant fpace left by
the afcending Clufter remains empty> it has been
obferved that there are fome in which that very
fpace itfelf becomes, after a time, filled with
a fort of Pith. The Dog-Rofe or Wild-Briar
of our Hedges gives an inftance ; and it is always
happieft in thcfe purfuits when the needful ob-
jeds are the mod familiar.

A Branch of this, with a Shoot rifing from
it, is reprefentcd at Fig. 3, In this the line of
the Corona left behind is very diftind;ly vifiblc
at ai and the Pith of the Shoot at 6 ; termi-
nating, as is always the cafe, convexly towards
the Branch* Thefe two parts are very diftinflly
known by their green and brown colour ; and
in the original vacancy at r there is found a
mafs of a kind of Pith, very coarfe in comr
parifon of that either in the Branch or in the
Shoot; and perfectly diftindt from both, com^
municatirig with neither.

In the Virginia Creeper, Fig, 4. the very Pith
of the Step^ is not continuous i; but ends obr

tufdy

Explained by the Microscope. 105

tufely upward, and obtufely downward, as in
the Branch. And in our own Vine it is not
only difcontinuous, but in the moft perfeifl ftatc
of the Tree is intercepted,' as at Fig., 5.

CHAP.

II.

of the Prolongation of the Shoot.

THE Prolongation of a Shoot already
formed, is plainly a matter of more fim>
pie circumflance than the production of a new
one : and here one would fuppofe the Pith, like
the other parts, might be found continuous:
but Nature, always confiftent with herfelf, the
God of Nature ad:ing every where in the fame
amazing manner ! confirms the doiftrine of the
feparate formation of that part, in the Shoots,
by its' appearance, lefs expelled here. — Be it
fuflFered, Lord ! to ufe thy name in honouring
thy worlds.

The

io6 The Construction op Timeek

The Prolongation of the Shoot in Trees is not
ft thing conftantly and regularly going on ; it
has its feafons and its times ; and takes its
courfe more rapidly at fome, more flowly at
others : and there are fomc when it nearly
ceafes.

Let ns follow its progrefs thro* a year j for
the fame is every year repeated : and tho' in
various degrees of greater and of lefs, of fwifter
and of flower ; it is the fame in all.

In Oiflober, if we feledl 9 Shoot of the A(b-
Maple, a qu|ck growing Tree, we fee its end
terminated by a cone, compofed of films. Here
the growth of the paft fc^fon has Aoppe^^
This cone is what .we call a Bud ; and thro*
thefe films,' at the enfuing Spring, the Pro^
longation of the Shoot is. to bp continued.
Such a piece is reprefented at Plate XVIJ,
Fig. J-

In this ftatc it remains thro' Winter; the
cold having clofed thofe pores thro' which the
Root ufed to draw in the greater part of its

nouriflimcnt.

Explained by the Microscope. 107

nouriiliment^ When the warmth of Spring
returns, the Roots fwell, thefc pores open ;
thofc vaft citterns the Sap Veffels of the Wood
Ibecome filled, and every thing is nouriflied
and begins to grow : the Shoot extends itfelf
thro* its films, and feems a young Branch grow-
ing ftom or upon the old one. If we let it take
its deftined encreaie till May, 'twill then be in
a condition to examine as to the nature of its
growth, and the condition of its parts. Such
a piece is (hewn at Fig. 2. entire ; and at Fig. 3^
fplit regularly open, with the fiflure carried down
into the Shoot of the former feafon. What wc
fee in it while whole is,- that the top has been
wpll covered with films ; and there is an appear-
ance as if the growth had come to an entire
ftop there: but in the fplit Shoot we fee 'tis
otherwifc ; there is a fwelling at what was the ,
top, a a ; but the brown Bark and the white
Wood, after thickening in their paufe, are con-
tinued : they afcend juft as the Cluftef from the
Branch, and leave like that a little fpace behirf4
them, e. In the new growth all therefore i^

continuous except th? Pith : the Veflels are only
lengthened ; but the Pith has ceafed. It comes
%o an abfolute terminatioUi^ in an obtufe forroi

io8 The Construction of Timber

as in the other inflances ; and after a fpace is

» . . ■ ^^ *

left^ Fig. 3. b bt ^ new Pith is generated in the
afcendihg Shoot, the fame in tcxtore, form, and
colour with that below: but, as has been juft
fliewn in the other inflances, perfedly difunited
from It. The new Pith therefore is not a con-
tinned growth of the old 5 but a fubftancc ;
produced, as that had been, from the othci'
"parts.

In this Maple the Pith has kept its cylindrk
forrn throughout, and not thickened at the end
with the fwelling of the top of the Shoot. In
the Pine, Fig. 4. where that fwelling is greater,
as it only affeds the exterior parts, a greater fpace
is left within than in the forn^er, as at Fig. 5.
but if we fplit fuch a Shoot, we find 'tis not a
vacancy that is left j the Pith fills the larger
hollow as faft as it is formed \ for 'tis, only at
the extenfion in length that its courfe ceafes.

In the Plane Tree, where the difpofition of
the Pith is more irregular than in many other
kinds, wherever the cavity extends, as at Fig. 6.

■

and y. a. the Pith always goes with it y but ftill
at the place where theShoot of one feafon ceafed ; -

and

(xHOWTJS-

OMiTSE CrOWJST ^'(^^fj-

y)utttej^

?^^>ey

t k

Explained by the Microscope, 109

and that of another begins, there is a fpacc
between the Pith of the former, and that of the
latter Shoot : b. And even in the Turpentine
Tree, Fig. 8. where this fpace is lefs than in
any other which has come under my obferva-
tion, ftill it is^ a fpace, as at Fig. 9. a. The
Pith of the preceding Shoot ends in the ufual
obtufe manner, where the beginning of that of
t^e young Shoot, altho* diftinft, is yet irregular.

BOOK

no The Construction OF I'lMBit

*rfi*i«MMi*^tiate.rifaM«MMI*^U«fcl

B O O K IV.

of the different Difpofition of the Parts

in various Trbe<*

^^— ^h^ j I - ■ (■■lafciiii lntf i ri < » ■

C H A P. I.

Of Differences in the Rind*

• i

THE ftrcngth of Trees depends upon
the conflitution of their efleiitial parts 2
their qualities principally upon their fev«-
ral added VeiTels. The effential parts; the
Rind» Bark^ Blea» Wood^ Corona, tod Pithi
are found in all Trees ; tho' differendy con-"
Aru£ted and difpofed: but the vafcular partSj
of this additional kind> are not only fmall and
inconiiderable in many, but in fome are entirely

wanting :

^■^■el^amscnni^"*

Explained by the MtCftdscoPB# i x (

viranting : nor is it ftrange ; for every Tree i9
not defigned to be medicinal.

The general nfiture and ufual di(po{ition of
thefe parts has been £hewn in one inftance^ the
Oak ; ia which they are all ^refent^ and where
they lie in their moft, regular form : butin the
variety of Trees which God has. given for dif-
ferent purpofes^ there are £> n;iany variations
from the general order of difpofition and mag->
nitude, that it is pleafant. in tbe light of curioiity,
to examine them ; but there are . alio higher
purpoies to be anfwered by fbch examination.
Since it is to the conftruiftion of that part we
call the Wood that Timber owes its ftrength j
and to the (izt^ and contents of the Vafa propria
aU Trees owe their powers and virtues 5 an eye^
thus accuflomed to the vifible differences^ will
giiefs, almoft to a certainty^ what ftrange Trees
are worthy notice^ as to durability i and what
promife ^urcs for fickneis.

To lead to. this diftintftlve method of viewing

them^ it maybe proper firft to fclc(a:onc of tbeleaft

complex of Trees or Shrubs ; the fimpleft in its

. . ftrufture :

112 The Construction of TimbeiJ

ftrudure : fince in fuch a one Nature will lay
open many things in the ordering of the parts^
which are hid in thofe of^ a more complicated
texture^

For this purpofe, ^ one of the fimrpleft o£
Shrubs, and one readied at hand every where^
the Dog-Rofe may be fele<%ed : and there will
be found in it, when examined frefh cut, and
in the growing feafon, a di(tin<3:ion of colour
in the. feveral parts, which marks their outlines
very happily.

If a piece of Dog-Rofe be chofen which has
.finished the growth of one feafon ; arid has juil
beg^n that of another, (for in this quick grow-
ing Bufh a Shoot acquires in a fhort time
fome confiderable thickneis) a fedion taken from
thiSi of about the two hundredth part of an
inch in thicknefs, will exhibit the parts with
wonderful clearnefs. Where colour is ufeful,
this degree of thicknefs anfwers better than
thofe (havings which carry but a thoufandth
part of an inch.

A quarter.

Explained bV the Microscope, iij

A quarter, cut from fuch a fciftion, and laid
before the fixth glafs of the Microfcope, appear*
as at Plate XVIII.

• We are to obfervc fifft, the Rind, d^ which i^,*
in this. Shrub, very thick, and ftands pcrfcftly
diftinguiChed in fuch a perpendiculjtr view from
the Bark, by its colour : it is a narrow line of
white, with foiall dots, which afe the Vafa
exteriofa in it ; ^. * Within this we fee a very
Inroad circle^ c\ which is the Bark, vtry thick
in thiis Shrub, and of a lively green. Thefc
parts' can never appear iii any inftance more
diftind. "A little way within the inner line of
the Rind, lodged in the fubftance of the Bark,
appear the Vafa cxteriota : thefe are of fo rtrong
a greeny that their colour diftinguifties them
from the Bark as much as their foi'm ; d.

• • ■

Within the fubftance of the Bark alfo, but
.toward its iftner part, and very near the Woody
lies the Blea, ^, perhaps better to be underftood
in this quick growing Shrub, taken at this
feafon, than in any other kind. We fee it,
in moft inftances, a pale continuous line be-*

H . tween

114 T"^ Construction of Timber

twecn the Bark and Wood; and fuch it will
become, after a time^ in this : but 'tis now in
the ilate of its foroiation ; and appears in feveral
convex pieces palpably taking their origin fronn
the Wood ; and as yet difanited from one
another. Its colour is a pale olive, and its
parts are very diftinil. It is evidently^ now
Wood, yet tender and but half formed, forcing
its way into tlie Bark, which it will thrufl out
to the very edge hereafter. The regular green
line of Bark, which feparates this Blpa from the
Wood, broad as it nov/ appears, will in half a
year more be nothing but that flender line which
feparates and marks the growths of the feveral
feafgns*

Within this laft mentioned green line we fee
the Wood of tl\e Dog-Rofe, f: even that is as
yet cornpofed of uncpnne&ed parts : and by this
view of Wood in its infant ftate, and by no
other, can we truly know what it is. It is now
a diftinft fubftance, in form of feveral ellipfes,
of a firm flrudture, and pale colour. Imme-
diately .within the bottoms of thefe ellipfes we
fee the embryo Corona, g^ confifling of a pale
convex .body, adapted to the ends of thefj
5 ellipfes,

•■., 'i

ExplaI!4ed by ^he Microscope, i'i^

ilipiesi. and formed by a reparation of the two
nembranes of their parietes> or fide&.

AA^ith what pleafute will the curious eye>
laving once acquainted itfelf with all thefe
parts in their didindt and infant (late^ purfue
them in other inftancesi where, in their adult
condition, they have united themfelves for
ftrength one with another ; and often loft even
the appearance of their original .conftrudion 1

The Pith in the Dog-Rofe is alfo a very
beautiful objed:. It has^ iii a flice of this
thicknefs, the appearance of ftarry forms^ with
oval fays : but this illufion vanifhes on cutting
a thinner pieces When one is viewed of a
thoufahdth part of an inch they appear only
fimple Blebs, ^'

I '

C H A E

1 r6 The Construction op Timbek

C H A P. 11.

Of DifFerences in the Bark.

THE Rind of Trees, being no more thj
an out-caft of the Bark, is of littl<
importance to them r and we find in it very^
little variation : but in refpedt of the Bark it is
mueh otherwife. This is a very efTential part
in the Tree ; the growth depending,, in a great
meafure, upon it ; and the qualities : aad we find
it accordingly very different, in fubflance, quan-
tity, and nature, in various kinds.

It is originally the outer membrane, covering
the Lobes of the Seed. Even there it may be
feen, juft as in the Branch of a Tree, in form
of a kind of fpunge ; compofed of flatted blad-
ders, la the fucceeding growth> the outer

ranges

Be«B

Explained by the Microscope.

117

ranges- of thefe bladders, drying, become what
we call the Rind •, for that part has no exiftence-
in the feed* ftate : it is Ibcmed by the operation
of the air ; it is ftretched by the fwellipg of the
Wood; and it is cafl off once in a feafon, -
as ihakes caft their /kins : but not entire,
only in fragments. Mean time the Bark re*
mains, covering the more fubftantial parts^ the
Blea» the Wood, and the reft, and feeding them
by a continual fupply of nouriOiment from its
ipungy fubftance ; always fupplied with water z
this it draws up freih as fail as it is drained off,
and continually fupplies every fubjacent part.
It proteds. all from external injuries alio ; and
defends them from the cffc&s of c6ld.

For thefe purpofes it is varioufly dlfpofed
in different Trees. In the hardy and flow
growing, as the Oak and Chefnut, it is thin :
in the quick growing, as Willow, Poplar,, and
the like> it is thick : and, what is more worth/
yet of regard, is, that altho' it be laid fmoothly
and in an even line over the Blea in moH Trees^
yet in fome its inner verge is radiated*

Thert

i' I

i \

tj8 The CoNSTRirtridN o? Timber

Thert are fomc Trees, and a gr^at tnan^
herbaceous Plants^ in which this part is con-
tinued inward, in form of rays, thro* the Blea,
into the Wood j and feems to fonn fo many
green wedges, fplitting as it were the fubAance
of both thofe parts. It would be difficult to
conceive how this were done, ' but that we have
feen in the Dpg-Rofc thofe more folid parts arc
not originally compaft ; but compofed of fepar
rate pieces : between thefe the rays of the Bark
infinuate themfelves while they are open^ and
keep their places, tbo' in a fmallcr compafs,
tilways afterwards.

. !

The Sorbus Legitima, or true Service Tree,
affords a very ftrong inftance of this : a piecd
of a tranfverfe fcdion of this Tree is givcri at
Plate XIX. This was cut from a Shoot in its
fourth feafon : we fee plainly at the lines of fepa-
TMion^aaa, the growths of three pcrfcft feafons ;
at i we fee thfc aft of growing in a fourth.

. The Wood is here, as .in the Dog-Rofc,
jhruft forward and outward into the Bark;
^nd that not in a continuous fubflance, as at ^,

but

SoRSirs Legituha

Explained by the MiCRoscopfiJ 119

^ut in detached bodies. They were fcgrpcntsl
ellipfes in the Dog-Rofe ; here they are cones^
brown Rind c terminsttes their fummits in
a regular circle ; but the Bark d infinuates itfelf
deeply among them, filling up all the fpace
l>etween cone and cone, to their very bafes \
and thehce continuing itfelf, tho' in a thinner
line, thro' every fealbn's growth of the Wood,
down to the very Pith, This marks out palpably,
by its courfe, the feveral parts which once were
- cones of Blea 5 as the exterior, yet retaining
the fame Torm of conTes, are the true Blea of
the Sorbus now : tho' In the courfe of growth
their taper ehds have fpread to the fame breadth
with their bafes. Here therefore, as in the
I>og-Rofe, and fome 'other in (lances, the Blea
is always a difcontinuous fubftance ; tho' in thq
generality of Trees it is one foft, but entire
ring.

The ufe of this conftru(3:ion in the oeconomy
of Nature is not difficult to be underftood: an
objedl familiar to me, in infancy, firft threw it
upon my mind. In the park of Sir Francis
St. John, at Thorp, near Peterborough, ftood
an old Service Tree, perfeftly diverted of its

, H 4 . Bark,'

isio The Constritction of Timber

Bark, yet growing and full of vigour. I remem^r
ber a thoufand times climbing it when a boy,
and to have heard wifer perfons fpeak of it with,
wonder; that a Tree thus naked could live.
I did not, even at a later time, underftand how
it could be, till, taking a cutting from the gardeii.
of her Royal Highnefs, this flrufhire preiented
itfelf to me. The coat' of Bark could be fpan^,
becaufe (here were rays of the fame fubftance
within ; which anfwered the purpofe.

Purfoing this fubje<ft I have alfo found that die
Ciftus Laurifolia, which has the fame conftrudlioQ
of rays from the Bark, lives very well whea
peeled ; and 'tis familiar that the Plane will do fb.
In that Tree alfo we fee the fame conformation ;
and muft no longer wonder at the fame efFe<5t,
There are many other Trees which have fome-?
what of this quality ; and in examining them
I have found they have all fome degree alfo
of this conflrudion ; and that,.(fo far as can
be judged) a degree juft atifwering to their
more than ufual quality of life.

■

Tl:iat Leaves and Branches fhould be pro-'
jiuced from^ a l^oUow Tree, whofe Wood had

perifhed.

ExiPtAINED BY THE MlCROSCaPE, I2l

|>erj(h^, tho' the*Bark was entire, could not
appear wonderful to thofe who knew the nou*
riffaaient was from, the Bark s but that a Tree
could live whofe Bark was gone, mud feeni^
lill this was known, almoft a miracle.

CHAP. III.

Of Particularities in the Blea.

TH E cohftruiSion of the Blea has been
explained in its place : but its difpofition,
and the arrangement of its parts, as they arc
various in different Trees, become now the ob^'
jeft of enquiry. The variations of Nature, in
this cafe, are endlefs \ and there are fcarce two
genera, wherein this and the other parts do not
differ, more or lefs, either in their quantity,
colour, difpofition, or arrangement. From the
gr^eai number of kinds which have paiTed under

3 »y

122 The Construction of TiMBBit

my eye on the prefent occadon, I (hall ieledl
thofe wheffe the dtfi^rence^ or particulaiities arc
moft confiderable ; and be happy in pointing
out to the attentive Reader what Trees, fb far
as this experience leads me, will beft entertain
his eye, and lead his thoughts to more enquiry.

I. Of the plain Difpofition of the Blea
in the Liriodendron Liliiferum.

When we would fee the'Blca in its plain,
moft natural, and moft fimple ftate, that Tulip
Tree which Botanical writers call Liriodendron
Liliiferum affords a very fair occafion, A piece
of this is rcprefented at Plate XX-.

Here the two Barks, a i, are very diftiiid: ;
the outer of a deep, the other of a paler brown :
and between, thefe and the white flefti . d is
placed at r a plain and even circle of the Blea.
Its pale brown colour keeps it perfedly diftind
frpm the iBark i and its ftrong inner margin as
plainly feparates it from the Wood. This is
the pure and perfect ftate of the Blea : and

were

I^miODElsrziKOX- LUiUFERVML

\ "b

■d

}

I
r-

Explained by the Microscope, 1^3

were it for the condition of this part alone
the Tree would demand a place here : but
it has beeii iele&ed for more particularities.
Nature is pregnant with wonder and delight;
and it has been the care, on thefe occafions, to
xhufe, among the number of thofe where the
main objeft is equally perfed:, fuch kinds as
afford therewith moft delight or n^oft inftrudion,
in the other parts. In this the Vafa interiora, e^
are very beautifully placed juft within the inner
verge of the Bark : their oblong form is An-
gular ; and the more fo, as it is lefssregular and
exad: than in moft cafes. The delicacy of the
Wood, fy and the arrangement of .the Sap-*
Veffels, gy in regular rays, are alfo worthy note ;
and much more their regular dirhinution in'fize
as they approach the Pith, h. 'Tis thus in all
Trees, at a certain growth ; but fcarce in any
is fo well feen, or takes place in the Shoot
fo early.

It has been obferved, in treating of the ,
Corona, that the ring or circle of that part
wherein the clufters of veflels are enclofed is of
the nature of the Bark ; this Tree gives a plain
proof of it at /•

IL Of

, I

124 Th*; Construction of Timber

II. Of the warped Difpofitioa of the

Blea in the Nerium Oleander.

The Blca of Trees admits of variations from
that plain and ordinary ftate wherein we have
rcprcfcntcd it before, both as to its^ difpofitioa
.and conftrudion : in fome Trees one of thefe
differences (akes pigce; in others both, The
form of the Shoots in. the Ofeandcr is not per-*-
feftly round, ai anid to this the Blea, as well
as the other conftituent part^ conforms itfelf.
(See Plate XXI.) In ihape it is i)ot a circle, as
in the Tulip Tree, but a fvvoln ellipfis, fmaller
at the ends, and rifing on each part toward an
angle in the middle ; and all this with great
regularity, b b. Its texture. is coarfe, r, and its
colour is a pale brown. The. parts of which
it is compofcd are the fame as in all other Trees ;
for one conftrudion goes through all : bi)t they
aft in this larger, in their cavities, as well as
thicker in their fides, than' in others. The
warped ftate. of the linfe this Blea forms round
the Wood, and the regular greatnefs of its parts,

moft

JVESirOi OXjE-ilSNllER,

/ k

:pi.g/.

■S

EXPLAINEI> BY THE MiCROSCOPB.

1^5

moft claim our attention : but .the objedt being
before us, it were blindnefs.nat. to xemark alfo,
that the Wood is delicately vafcular, di that
the iline which > is to* mark the growth of
another feafon is thicker than ufual,:^; that
the circle of the Corona is palpably, of the fame
6dk>ur:and fubilance of the Bark^/^ and thit its
dufters arc thrown together more than ufual on
the inner fide, ^5 that the Pith is Remarkably
large, h ; and that the Vafa exteriora, /, and
interiora,->ti fhew themfelves with a diftindtnefs
very plcafing* There are two rings of the
interibra very large and fair, and a pcrfedt line
of the exteriora, at the very verge of the Rind.
What juice thefe laft contain it has not been in
my power to ' determine j the former have a
milky acrid matter in great abundance.

III. Of the undulated Courfe of the
Blea in the Nerium Zeylanicum,

Purfuing the conftru(Sion of the Oleander
in another fpecies wp fee by what gradations
Nature bri&gs about her changes. The Blea in

the

126 The Construction op Timber

the Nerium Oleander was warped ; here it is
undulated: there it ran out into four obtufe
angles ; here it forms a multitude ; a continued

ieries of them : in thisj as m the former in-^

< •

fiance, <:onfbrming itfelf to the fhape of the
young Shoot ; which in the Ceylon Oleander is
neither perfedly round ^ or elliptic^ but all the
way raifed in an uneven linei| or in a kind of
ridges and furrows. In the ilrucfture of this
Blea we find a yet more confiderable difference :
it is a broad line of a pale whitifh fubftancet
formed of veffek with coats fo remarkably
thick, thaf: Nature furnifhes no inftance equal
to it; (fee Plate XXII. a a.) and the fpungy
matter which fills their interftices is in like
manner preflcd clofe and compadt. The colours
alfo, in a frefh cut piece, afford a very good
opportunity of marking all the conftituent parts
in this Shrub to a nicety; and I hope it will
therefore bec©mt familiar in the coUedions of
the curious. The Rind is thicker than in
moft things, i; and the Bark, c, of a very
delicate texture : the Vafa exteriora, ^, are very
numerous, tho* not fo large as in many others g
their quantity making amends for their want of
faze. Their difpofitipn feems but irregular;

yet

-£ ,

Explained by ,the Microscope, • 127

, yet a careful eye will count two ranges of thtfm«
The Wood, e^ has fewer Sap-Veffels than ufual i
and^ what is much more ftrange, they ar? not
perfe<5Uy round, f: the undulated outline of all
the conftituent parts perhaps preiles upon them*
ThePith,|f, is immenfe, and theCorona,i&, fmall:
but Nature, confiftent with herfelf, has given
to the cluders of that undulated Ring the fame
difpoiition within the line, as in the common
Oleander. '

I
/

IV. Of the diiForm Blea of the
Ephedra Disticha.

We hav(5 in this Shrub an inftance of the (port*
ings, .as it were, of Nature, in the Blea ; per-
fedtly fingular. It is confiderable in quantity, a ;
it furrounds the Wood in that kind of undulated
line mentioned in the preceding inftance ; and to
a correct obferver it appears very diftindly to be
of different textures in its dilFerent parts: a*
line of Veflels neareft the Wood, and a mere
mafs of confufion behind it, toward the Bark,
This will not be difficultly 'Underftood by thofe

who

128* The Construction of Timber

who have firft acquainted themfelves with the
compoiition of the part. We have feen it i»
conftruifted of vcffels and an int^rftitial fpunge*
All that is fingular hete is that the fpunge
ufually placed between vefTel aqd veiTel is kept
feparate, and thrown behind* A fed:ion of the
Ephedra is given in Plate XXIIL and thefe two
parts of the Blea are feen at ^ i. c 2. But the
Ephedra gives us much more matter of delight
. and wonder. With refpedl to its Rind and
Bark^ a ii and the difpofition of the Vafa pro-
pria interiora, /; (for extqriora it has" none :)
th^y differ not from wh^t is the ufuat courfe :

but the Wood, d, which is delicately con-

' ' ' ■
ftru6ted^ (hews the diminution of Sap-Veffcls

toward the center very diftindlly : we even lofb

them near the inner part of the laft grown

circle of the feafons. But^ bs&de this, that

beautiful advance of the Wood toward another

of thofe circles ; that which charmpd us in the

Dog-Rdfe, raifes raptures here. We fee dif-

tinftly at e the pulhing for a third circle of

Wood J and here know how it is formed. The

parietes of thefe fniilrums of cones, which in

this objed: anfwer to the ellipfes of Wood in

the Dog-Rofe, are extended in growth before

the

»^

Efkedr^ Dzs ticha ' '^\

\ \ ^\ ~N, '~e

c.a-

ExPLAiNED BY THE MlCROSCOPE, 120

the matter of the Wood is formed to fill them.
It is palpable, iii a good view of this kind>
that they are well marked, but perfeftly empty.
The Corona is very beautifully hollowed ; and
in the Pith are palpable Veffels. This i§ the firft
occafion that has offered of naming them ; but
vre Ihall fee them in Ibme other inftances.
TThey are the Vafa intima, fo ftrangely difpofed i
this their ftru^ure ihews, and the firmnefs of
their contents. Thefe pierce the Pith in a
longitudinal diredlion ; or more probably they
are primordial in the ftru^dure of the Plant,
^ and the Pith is formed around them.

CHAP.

r *

130 The Construction of Timsex.

M "ili

CHAP. IV.

Of Particularities in the Wood.

I. Of its fimple Strudure in the Com-

men Dog-Wood.

ANEW thicknefs of Wood is given to
a Shoot at every Spring and Midfummer ;
diftinguifhed by a circle, marking the place
where the former ended. The ufual appear-
ance of a fedtion in this part is that of a mul-
titude of rays^ proceeding from the Blea toward
the Pith; cut in many places by concentric
circles ; at different difiances. But the number
of parts confounds the eye ; and to know what
the Wood is, we are to feek it in fome iimple
flate* No inflance affords this better than a

fedion

£xPLAiNEC SY The Microscope. 131

leiSlion of a young ShoQt of the common Pog-
Wood. If we fdeS one from a Branch that
has had but oAe fcafoo for its growth, the
appefiranpe it give$ before the MIcrofcope is that
figured fit JlateXXiV. When we have caft
aa eye upon the Rind an4 Bark, and the broad
pircle of the Blca, h c^ we fee the great,
plain, ^nd npblc ftru<fture of the Wood at //;
-and find at e^ what we had before fcen in the
JDog-Rofe ; that the Corona, howfoever after-
^£^r4s it he filled^ takes its original from the
|>afA^e s or fides of thofe obtufe brqad cones
which here are what the cUipfcs are in that
QUbcr Shrub. And it is palpable that here in
the Corona, juft as in the protrufion for a iecond
feafon's Wood, thefe parietes are the firft part

; that grow. They form the fpace which there

\ is to be filled with the matter of the Wood;

' an4 here, by a much more complex and won-

[ derful fubftance.

The. Wood is in this inftance the mofl: plain
and fimple thing imaginable ; jind its parts
being naturally large, and not prcfled together
AS in the harder Jcinds, can be viewed diftindly,
and eafily underftood . We now fee that the Wood,

I a which

132 The Construction of Timber

which in old hard Trees we look on as one
mafs, is formed of cones, with bafes tending
outward, arid each cone perfeftly inclofed in a
thick fheli, ojf a matter more compaA by far
than the intermediate fubftance. Within thefc
cones run multitudes of rays, all like the parietes
of the cones, converging inward 5 and in reality
each two of them forming a leffer cone, within
the larger. Within this leffer cone, between
thefe rays, is depofited the fubftance of the
Wood, pierced with innumerable holes ; or, in
a more juft way of fpeaking, giving place to a
multitude of Veflels. Thefe are the Sap-Veffels.
The intermediate fubftance is the mofl: compad
part of the Tree : and this is always the real
ftrufture of that part ; however it may in various
inftances feem to flicw a wonderful variety.
The Pith of the Dog- Wood, /, is, as the reft,
the fimpleft: we can look upon ; a mere col-
ledion of hollow cells crowding and preffing-
upon pne. anpther.

If this conftrudion of the Wood, which is
fo cafily understood in the prefent inftance, be
always held in mind, as we examine others,

the

TfOGWOOU

Explained by the Microscope. 133

the fecrets of the compofition will be laid open
to us with lefs pain.

II. Of the Length of the Cones in

the Acacia Degidua.

A Tree which affords an inftance of equal

fimplicity with the Dog- Wood, but .in a new

form, is the Acacia Decidua : a feftion of which

is given at Plate XXV. yet the fmallnefs, or,

if it may be better underftood, the delicacy pf

its parts renders it lefs obvious ; and leads us,

as' by a fingle ftep; from that fimple kind to

the appearance of the more complex. , The

Rind in this Acacia is very thin ; the Bark is

alfo thin ; a 6 : and in the Blea, which holds

ibme breadth at r, are difpofed Vefiels fo very

much refembling the inieriora pf other Trees,

that we (hould fuppofe them of the fame nature,

if we did not firft fee them in a place where

the intima alone can (land ; and if the firmnefs

of the njatt^r v/ith which they are filled did not

confirm it : but beyond all, their own ftrudure :

. I 3 for

134 The Constrxtctiow of Txmbsk
for they are fimple, Veffels } dieir tides are nd

vafcular.

The Wood, which lies nearly within thefe»
confifts of very long and narrow cones. The
parietcs of thefc sttt exttcntely diftin£t» tbo*
fine i and the whole Wood is pierced with Sap*
Vcflels ^ large, that its own vafcular ftrufturc,^
which is indeed in all Wood Very delicate^
affords the idea of a c0nspa<£t ind £>Iid fobftance.
Nator», in this inftance, giv^ing all to the Wood,
contrails the Pith, znd half «f>ni)i8att& the
Corofta: 'tis very Angular: bat ft ill thfc parts
of that circle are to be fecn in thefe young
Shbots of the Acacis^ Decidud: and in thafi
of more ftanding they become as large as tifual«
Why and to what end Nature, Where nothing
is done in vain, gives thi^ exuberance of Wood
to this, and the fcanty ftore of it to Dog-Wood^
are queftions foF a very high philofophy.

III. Of

^C^CZA DECIDZr^

Exl^tAINBD BY THE MICROSCOPE. 135

III. Of the thick Parietcs of the

ROBINIA CaRAGNA«

He who will join with me to purfue the laA
Darned plan ; and try if it may be found why,
in the Robinia now befwe us^ the ddes of thoi^
cafes wherein the Wood is held are remarkably
thicky or, if we may ufe fo ftrange a word,
fo coarfe; will perhaps open the way to a
knowledge of the nature of Trees, which,
tho' propofed more than two thoufand years ago
by Theophrailus, has pafTed thra' the hands of
all his fuccefibrs untouched. To far as their
writings have informed usi therefore, at leaft,
not happily followed.

The appearance of a fedion of this Tree is
given in Plate XXVI. In the Rind and Bark,
a b^ nothing is particular.. The Blea is very
firm, compact, and delicate. In the Wood there
are, as it were, fhadows of circles ; nothing
real : but ftill we find the Sap-Vcflcls dilpofcd
according to the fame divifions. The great

I 4 ribs

136 The CoNSTRUctiQN of Timber

ribs whiph mark the feparate cones are objeds
indeed of wonder ; thick, firm, giten, and ftrait
as lines drawn from the circuqifereQce by a
geometrician ! It feems as if thq effort of Nature
in the conftrudion and growth of this Tree ha4
been placed hi^re ; and that thefe ribs had out-i
grown the divifioh of the feafon circles. Thofe
circles mark tlie ftops of growth between the
Spring and Midfummer encreafe : it (hpuld ap-
pear therefore that this Tree owned no diftindioti
of thofe fe^fons j but that it continued equally
at all times growing on. 'Tis fihgular in many
things ; .in nothing more than this.

The Corona is fmall, but regular y and in the
Pith are Veffcls, fluffed, as the intima always
are, with a concreted juice, like a hardened

relin.

IV. Of the broad ^ Seafon Circles in,

the Arbutus.

The parts wc wifh to note in Trees for their
Angularity are beft fhewn by oppofition. In the
Robinia Caragna the circles pf the feafons fcarcc

(

JlOMZxz^ C-AJt^axc^

J>l.s£

■d I

, 'b

Explained by the Microscope. 137

cxift : in the Arbutus, a Tree which few exceed
in delicacy, they are yet remarkably confpicuous.
A view of this is given in Plate XXVII. In the
Rind, the Bark, and the Blea, a, b^ r, nothing
is particular 5 but in the whole conftrudtion of
the Wood there is a delicacy which fancy fcarce
can reach. There is much more : there is a
diipofition of the Sap-Veflels ftrange and un-
ufual ; they are largeft toward the bafe of every
circle, and become obliterated gradually to the
verge. In the common courfe it is quite other-
Mrife : but the line f^ the mark of diftinflion-

^ between the encreafe of a former and a latter
ieaibn, is, in the Arbutus, thickened beyond
what we fee in mod kinds : and even the *
exterior part of the jfirft circle from the Corona

' is thickened with it. The Corona, ^, partakes
of the delicacy of the whole ftruc^ure of this
beautiful fpecies ; and, tho' fmall and thin, and
more than in. moft other kinds tranfparent,
afibrds a view of all its conftituent parts very
perfei^i and very lovely.

V. Of

138 Tflt CON8ritUCTl6^^ OP TlMBt*

V. of the uneven Lines in the Wood!
of the Thuya Chinensis*

Our attention was demandedi in a preceding
inftancc, by the perfeft regularity in which the
lines formed by the parietes and inner divifions
of the Wood were drawn from the circum-
ference to the center, even with a mathematicdl
exadtnefs : we have here a proof / bow much
Nature can deviate from what might feem her
deflined rules; yet without alti&ring the, c(m«^
ftruifiion of thofe portions with the difpofitibn
of whofe component parts fhe wantons. A
iedion of the Thuya Chinenfis, the China Arbor
Vitae, is one of the moft delicate objects diat
can be placed before the eye : in this m^nlle]^
•tis reprefented at Plate XXVIII. The rays or
lines whi^fa divide the Wood into innumerable
fmaller cones arc here thrown into an cafy wave,
which, taking its rife from the inner line of the
Blea, bends downward in the new circle, then
fifing in the fecond and third, takes again its
firft courfe in the innermoft; and this with

TlTUY^ CsiN^ElTSIS

EiPLAINEJJ BY THE MtCAOsCOPt:* 1 39

an eafy bend that is very pleafing. All the
time the parts are as diftind, and their quan-
tities and proportions are as regularly kept, and
as well obferved, as if the lines had run with
the mod perfeft ftraitnefs. For the reft, what
is obfervable in this fine Tree, is, that the Pith
is extremely fmalli the Coronli very delicate,
but finely formed, and it runs into deeper
angles than is ufually feen i the Sap-Veflcls of
the Wood are largeft in the youngeft parts of
it ; and the Vafa propria extcriora are very
diilina-

C il A P.

140 The Construction of Timber

CHAP. V.

Of Particularities in the Corona of

T RE E $•

I. Its Plainncfs in the C i s t u s

Laurifolia.

THERE can be no doubt but the con-^
ftruilion of this cflential part is perfeftly
the fame in all Trees : the ftridcft obfervations,
and the powers of the greateft glaffcs, join to
fhew this : but here, as in the Wood, and elfc-
where, altho' the parts are invariably the fame,
their difpofition differs wonderfully. In the
Ciftus Laurifolia, Plate XXIX. the Corona is
little more than a plain ring, a: in which,
howei^cr, wx fee eafily the fimple ftrudure of

the

CrsTtrs X^tauFOj}!^ >

Explained by the Microscope. 141

the Bark in the outer part» ^, unmixed with
other matter. In the portion next the Pith,
that darker line it firft exhibits, r, ihews, when
viewed with due advantage, the clufters, J, on
which all future encrcafe depends. For the
reft, . the coarfe form of the Blea, ^, is Angular
in this Shrub ; as is alfo the thicknefs of that
line which terminates the Wood toward the
Blea, f. The Sap-Veflels, g, in the Wood
itfelf are fmall, but finely * difpofed ; and in
the Pith, Jb, there are fome clufters of the Vafa
intima, /, whofe contents are lefs compa<ft than
thofe ve^fels ufually have them^

II. Of the Exterior Prominence of the
Clufters in the Magnolia Glauca.

The Circle in this beautiful Tree does not
carry the iimple outline of the Ciftus : its
clufters are not buried in its fubftancc. The
whok of the Corona of this Tree, a fcftion of
which is given jn Plate XXX. is of an undu-
lated form, ^ ; and its wavy prominences, ^,
which are but fnwll trnvard the Pith, fvvell out

into

142 The Construction qf Timbbi^

into the form of obtufe jtnd u^cqu^l confS
toward the Woqdt c ; whofe firm texture giv^
wiiy to thf nit vnd leavef ihwi their appointed
figure, lata e»ch of thefe prpminences is
cj^rrled one difliodt ^d per£e£): clutter/ d^
wherein all the part; are very vifible, and the
V^ffels of the different orders are rood diftiu^y
ieen. The view here given was taken vfi^
one of thoie wonderful glailes made by the
l^ere de Torre> placed in the apparatus of the
dopble Microfcopey inilead.of the tube. Nothing
could fhew an objeA more diilindtly ; and the
reverend father deferves the higheft praife ;
whatever fate prevented his receiving it from
our Royal Society : whatever blindnefs, or ma-r
levolence there> injured his fair fame.

What is obfef vabic farther in this noble cfcjcdt
]S> that the Blea> e, has in it a regular and
conncfted chain of v^ft vclTcls, perhaps exceed-
ing the Vafa intiipa in apy other Tree; and
that behind thefe, in their prpper place, the
fubilance of the Bark, there is 9\& a regular
courfe of very large Vafa propria intcriora.
Tbefe promife virtues in the Tree ; for they con-
tain thick juices : but they are yet unknown.

III. Of

FLgc

/ y>

■b

£XFJL4.|MS9 BY THB MlCROSCOF£. 14.3

III. Of the Intierior Prominence of
the Cluftcrs of the Corona in the

Staphyljea.

The common Bladder-Nut, Pkte XXXI.
ailbrds the Mioroibopey in this way, an objeift
cf great h^auLtys and» in the conflrudtion of
the Corona, ^, the part her^e upder immediate
confidenation 5 it is of proper fingularity alfo to
follow, in the minds eye, that of the Magnolia.
That circle here rifes, as there, into protu-
berances, in form of obtu& cones : but, as
in that Tree, they ar« thnift outward into
the Wood J hcr6 they projeift inward, 'and form
an indented line about the Pith« a b. Each of
^ie£b protuberances, as in that iinflanos, con-
tanifi im^ of thofe clufters from which the
encisafe of the Tree is made by new Branches*

The JSark in .this Tree alfo is delicately con-
ftruiftcd, ^; and in it are a feries of very
heautiful Vafa interiora, c. The Blea, V, is
ahnoft BJOthing i a mere white line feparattr^

'' the

144 The. Construction of Timber

the Wood from th€ Bark. The Wood, e^ is
delicate ; and the Pith, /, being formed of
fhallower Blebs than in many other kinds,
affords a very pleafing mixture of double,
treble, and quadruple lines \ in various figures.

iV. Of the Projedion inward of the
Clufters in the Pluknetia Volubilis,
in Form of Cylinders.

The uttdulated line, with^hc protrufionr af
its rifings into a kind of cones, is not the
higheft effort we fee in Nature, -under this
head. The Pluktietia, Plate XXXII. affords
us. an inftancc where thofe protuberances, every
one of which is as it were the coat or fhell of
^ clufter of propagation, form themfelves into

abfolute cylinders; and feem continuations of
the parietes of the cones of Wood j making at
leaft the outline of thofe cafes. The circle, ix,
of the Corona here is plain and perfeift Bark ;
no way to be diflinguifhed from that at b but
J3y the fmallnefs of its parts: but the protu*

berances.

Pi^vcicfrETiA. VojjUBinis

3'-

BxPLAlilED BY THE MlGRC^COPEi I45

iterances, c r> altho* they carry the fame kind
of outline with the Wood, d, are pcrfedkly dif-s
ferent in their contents;

It h^s been obferved before, that the out-
line of the Corona is always firft formed by
at duplicaturd of the fides of the Wood cones %
and what we fee in this inflance is an evidence
6f that conformation, the traced of which re*
inairt longer tllan in riiofl other Trees, ^The
Conftruftion of this Tree dbes not in any thing
elfe material differ from the ufual CQurfe^ unlefs
it be in a fuperior degree of regularity and
^ftindlnefs of lines j ^,

e H h%

■ . ■-• n

I *

^46- TsB CovrntQerioii or Timmsk

CHAP. VI.

I,. Its pkin State in the AifMONii

Sqjjammosa^

r . <

THE Pith, lying immediately within the
Corona, muft in all cafes take its form
,fi:om the interior outline of that part; for 'tis
too foft to have given the figure to the Corona :
not to fay that it is always poftnate, and was
^'ffofr ii| bep^ng when thaf; line was formed. In
the Annona, Pl^te XXXIIL we fee it in what
may be called its fimpleft and m6fl: natural
fiate. It fills a regular circle exactly in the
center of the Branch, and has neither protube-
rance nor indenting! y*j and it afibrds all that

^ijzifojsrii

£xpiAlN£D BY THB MlCROSCOP£« I47

delight to the eye in viewingj that a Pith ia

t:apable to give ; for its cells are very fh^UoWt

and the films that form them very delicate :

fb that in viewing a piece of about an hundredth

part of an inch in thicknefs, fuch as is repre-*

fentcd^ hcre^ wt fee thro' a vaft multitude oC

them at once^ whofe outlines interfe£ling one'

another give cobweb-like. ftars 5 and forms of

great variety and beauty.,

For the reft^ the Annona Is no trifling obje£):^'
Its £lea, e^ is greater i;i quantity and more difi-
tindlly formed than almoft in any other Tree*
The Wood is regularly diipofedy and pierced
ty numerous Sap-Vcffels/y*.* and in the fub-
ilancc of the Blea> g, are Vafa intima^ A, greater
thaii in many other kinds*

il. ' of the Pentangular Form of the
Pith in the Almoni>*

We need not always fearch the ih)ve$ for
Trees or Shrubs to afford delight in this exa-
laination 3 our gardens^ nay ^in many inftances

K z the

1J^,9 TftE Construction of Timber

the hedges^ afford them. If elegance of ftruc«*
ture alone were fought, and beauty were the
objedt in purfuit, fcarce any kind affords it in
a degree beyond die Almond. But beiide this,
it has al(b great (ingulartty ; and is in many parts
moft worthy of obfervation. Plate XXXIIL

In moft Trees the Pith, conforming it-
felf to the other coats, takes the fame fhape
with the outline of the Twig. 'Tis round
we bi^e feen in the Annona, ^nd in the 01ean<^
der 'tis elliptic, and angulated; in each cafev
anfwering ta; the fhape of the Shoot : but tho*
the Twig of an Almond Tree be rounds the
Pith is pentangular 5 yi This form is given .it
by the Corona ; which, tho' extremely narrow,
yet preferves that £hape with the moft trim
exadnefs. The Pith anfwers in delicacy to the
Corona s and is tender, thin, tranfparent^ and
▼cry prettily figured. But in the Almond there
is more worth notice : the two Barks, a and ^,
are thicker than is ufual ; 'and in the fubftance
of the' latter lie oval Vafa interiora, c, of great
note. The Blea, d^is formed of little cones
turned toward the fun, and between thefe runs
in a quantity of Bark, ieparating alfo for a little
3 ' way

Fetil^^ C02/1FES.A.,

ExPtAJNED BY THE MiCROSCOPE. I49

way the cones of Wood, The Almond fliould.
therefore be in Nature another inftance of a
Tree that may furvive when peeled : and what
it may be, that it is : many Almond Trees at
Denham fhew it. The Wood in the Almond
is delicate ; but as the Barks are thick, fo are
the lines which .divide the circles of the
ieafonis.

III. of the PiTp of the Petr-sa
Conjfera; not Central.

The fportings and the wantoneflcs of Nature,
(if fuch expreffions may be ufed on unoffending
fubjeAs) have been fpoken of: doubtlefs what
vain philofophy has taught us to call by the idle
name Lufus Naturae are things referable to
caufes that would exclude the term, if they
were known^ But howibever that may bft, the
Petraea Conifera, Plate XXXIV. gives a very
ilriking inftance of this kind. One would fup-
poTe,^ if , any thing could be called certain about
the Pith, it would be its central difpofition : at
Jeaft it might be thought fo in refpei^ of young

K 3 Branches!

i^o The Construction of Tim^ei*

Branches } for they have not been in the way
of thoTe accidents which might have thickened
one fide of a Trun|c at the expence of another :
but here we fee that great difpofer placing, even
in the youngeft Shoots, the Pith for on one fid?
of the Bough, a. The P^traea iLffofdt us alfo
an inftance of one of the fimpkft Pith^^ fur*
rounded by a Corona as little confiderable as in
any other : but in the Wood of this Tree, ^,
there is as much Angularity in conftru<Sion, as
of the Pith in place. That part is formed
of very broad, very obtufe cones^ whofe parictes
take that wave fo delicate in the Thuya Chi-
nenfis ; and confequently the interior lines have
alfo the famfe turn. This adds not a little to (he
prettinefs of the objed:, when a fetfHon of the
Tree is viewed : but there is more to be ob-

, ^ ■ . • -«

ferved on this head : the Blea, r, is very con-
fiderable in quantity, and pierces the Woo4
between the greater cones ; juft in the way the
Bark has been fhewn to cte in many Trees.
It were well if this fbecies were more common,
that we fnight fee whether of not the Blea
could ferve the purpofe of the Bark in its
growth 3 for here, as the Bark is jpcrk&l^

^ feparatcf4

ExPliAXmSD BY THB MiCItOSCOPSk ' tjl

ieparated from the Wood, if on the peeling a
Branch of Petrsa it ftill continued to gtow#
W€ &eoiuci know ute Blest can ferfc uifr odmc
pf that part, as well as that which is imiae«
lliately its owiu

••'

BOOK

152 Thb Construction OF Timber

• •I'^f

^Tse

^^^^ S ia ^^ SZIZSSSC

BOOK

Of Partijcularities in the V e s s e l |

of Trees.

<ryai

CHAP. I,

^Particularities in the Vasa Propria

£ ¥ T E R I o R A.

■i

THERE i$ no part of the Vegetable Codt
.ftrudlion £0 little liable to. variation, a$
far as I have yet feen^ as this of the Vafa pro-
pria Their form and diipofition in the Oal^
has been given already j and that is^ in ^Imoft
f very Tree, the true ftatc of their arrangement.

The^r

Amkiuc-an- Cyipubss

^i-3J

Explained by the Microscope. 153

^facy ^re often too fmall to be very obfcrvablc :

cbe eye frequently milfes tkem, unlefs aflifted

by fome new power of glaflcs : and when it .

finds them^ -they arc juft what they were ia

kinds that offered them more eafily to the view.

Only in the American Cyprefsj reprefented at

Plate XXXV. I have' feen a difference : and

'tis there indeed a great one. In other ihftances

they are packets of little Veffeh ; tender, thin

in the coat, and filled with fome tough juice. In

' this Tree they are fingle tubes, ^, their coats arc

firm, they rife up aboVe the furface of the reft

of the parts when the feffcion has lain cut a little

while, l[that is, they con trait Icfs than the other

parts, which therefore recede from them,) and

they are more than filled ; at leaft 'twas fb at

the fcafbn, April 17. when I examined them,

they run pver^ with a moft pure and perfedl

balfam 5 nay they (hew their fides, tho* thick,

unable to refift the force with which this has

been thrown up Into them : for they appear

bUrft in many places.

For the reft, this Tree is not without its
particularities. The Blea, c, rifes in cones;
jind the Bark, ^, forces itfelf between them ;

but

1 14 The Construction or TimbbH

but does not penetrate tfeie-Woo^ aei io fotbt
other inftances. The texture of the Wood^ #»
U very delieatp j and the Sap^Veflelsj j^ are
nuoierous/ but not large. TheCofoaa, g^ h
liiis Tree is finally but veiy ooFrei^j defined;
9nd the Pith^ b^ is extremely tfain^

- 1

v».'>^ •"

« s

CHAP. n.

Particularities in the Vasa Propria

JnT£RIORA,

I. Their fingle Diftribation and fmsill
Number in the Larix,

F thefe important VelTels, (important in
their ufe. to man, tho' as \% fhould ieem
le{^ fo than many other parts to the growth
of the Treei) we fee a great variety, in iiUm-*
ber,^ difpofition, and contents : but in all^^
whatever may be their difference of fiz?, their

ftrudlufe

EyFLAIKED BY THE MlCROSCOPK. t^f^

jflrufture is the fame. To underftand them
beft, the way is to fee them where they are
fimplert and mbft diftindt. The common Larch
Tree is here feledled for that purpofe. In the
fcdion of |t, Plate XXXVI. we fee, in the
-great fubftance of its Bark, ^, the mouths of
a few Veflels ; few, but very large. They are
very conipicuouily diftin<f^ *, and ^rve, in this
light, to. that moft ufeful purpofe, the clearing
up a doubt, which' fomc who have gone thro*
jtheie obfervations with me had entertained.

The yaftnefs of thefe Veflels in fqme Tree?
had rendered them fufpeilcd not to be fuch,
till I (hewed turpentine exadtly filling and
puzing up from them, on cutting in fbme kinds
of Pine : and in others their fituation without
the' centers of diftin(St cones of the Wood, con-
founded them in the imagination with thofe
protrufions of the parietes which are, as has
been fhewn* the beginnings of encreafe in that
part* But here alfo the Larix afFprded a diftind:
anfwer to the doubt. The Wood of this Tree,
tho' extremely delicate, ^, is not formed into
large corteS at all, but difpofed between the
feveral radii only : yet here appear thefe vaft

openings.

156 The CoNSTRircTiON of Timber

cpenii^s, d as in other cafes ; and they are
filled with a very lingular kind of liquid
mailick.

For the reft, the Larix affords a very pleafing
and inftruiftive view. The Rind is thicker than
in moft Trees ; and clofe within its verge, be-
tween that and the Bark, are lodged the Vafa
exteriora, J, in long and (lender clufters,
which at the laft- mentioned * feafon diftinguifh
themfclves eminently by the juices they con*
tain, they being of a high crimfon. The
Corona, e, is very beautiful in the Larix i and
its Pith, jT, is clear.

il. Of their clofe Difpcfition in the

Tanacetum FrUTICANSs

The number of. thefc Veflels niay bd much
greater, tho' 'in a fingle feries, than we have
feen them in the Larix; The Tanacetum
Fryticans, a fedion of which is given at
Plate XXXVIL is an inftance of this dilpofition.
In this lingular Shrub, which fo far approaches

i tQ

Zi^iias.

-n.s6

)

Explained bv theJMicroscope. 157

to the herbaceous kinds as to be almofl all Pith^
wc fee them in the fubftance of the Bark, at b^
extremely larger and placed fo near, that the
€ircumference, inftead of- three or four in a
quarter, here contains jGix or feveii ; the Plant
having from twenty-four to twenty-eight in the
circle of the Bark« In the reiinous, and in fome
of the gummy Trees, we always find thefe
Veffcls filled with their proper juices. In this
Shrub I have, on the contrary, always found
them empty, c: but near them, and behind
them, are difpofed other Veflels, d^ large, tho*
not like thefe, and clofe arranged in a regular
connected line : they are at all times filled with
a peculiar juice; tough, fragrant, firm, and
coloured. Nature has not allotted the fingle
fcries of Vafa interiora, as by an inviolable law
belonging to all Plants ; we. fhall fee them, in
a fucceeding inftance, in much greater quan-
tity : and here, tho' it be lefs diftinft or obvious,
the cafe i& Juft the fan>e.

. The farther particularities in the Tanacetum
Fruticans are not a few or flight ones : glands,.
^, in the form of hairs, hang on its outer Rind i
a thing common in the herbaceous tribe, tho'

- . - It

ijS The CdNstttirCTidN of Timber

it bo leTs fo in Trecs^ The Bla» / fbrms tti
tmdttlalicd lifle» of a clofe tesrtuce ; and iipme-
diatdy ^itiiin that ftands what> tfiere is of
Wood^ g ; a tliin loofe circie» foftned ndt into
cones, but oval bodie9» and feparated by die
matter of the parietesy ran o<st into a kind of
^ngCy and forming a tegular circle under the
Blea. The Corona, i6, is a circb of inore thaai
nfual circumference ; and Nature has allotted it
accordingly to be very thin : and the Pith, id
which is of the fimpleft kind, by far excc^
in quantity all the reft together.^

III. Of the Various: Scries 6( the ^asA
Propria Interiora in the PiNUf
Cembra<

If the place of the fupernumefaEty VefTcfe,
in the preceding inftance^ could lead us to a^
doubt whether they were or were hot in reality
of the nature of the Vaia exteriora ; what was
there conje<^ttre, here atnounts to certainty.
The Pinus Cembra, a feiSion of which h given
in Plate XXXVIII. befide its iiqgle range of

• immenie

Ifomenie Vafa iexl^iora> a^ placed in the uCimI
w»y ifi iit« th^k.Sark, has two or more h^
prderly twget of VtsfS^ls^ palpably pf the hmg
mstarc : aad w^n h^&de thefe there i6 a ring of
finaller Ve^s^ t^ {fxrro^i^g, at a litde d^*
tano^^ efich of the larger^ 'Ti» happy tli^t iii
lihis Ti^- the Jwf:6 wb^b fUU the great Vai«
pTQpi^ is jS> pVK ani find a torpentine;^ £1^
aby^^at m it» ^9mity$ aiid Ca^ peculiar m its
^diU that th«f e cpuJd nised fio iDore pr better
iteft ffir^h^r th^e atl^r VeiTels were of th?
jfaoH: iindf than whether they did pr did nol
^arry the faii>e pepulUr juice. Th« tip of «
peacii touched upon their open mouths d^er^
uiifm$ this perfef9tly#

What then? if further obfervabli} in this Tf ce^
is, that tbe Rind> c, is thick, which indeed is^
lefs unufual in the refinous Trees than thofe
with watery juices ; that the Bark, J, is alio very

^ thick, and very delicately formed; the cells being;
more diftindt and yet with thinner edges than:
in moft Trees : the Blea, e, is a firm, duflcy,
cJompad: circle. The Wood, jfl on the other
hand, is tranfparent to a * degree fcarce feen in

' any other Tree, except thofe of its own genus,

and

l6d The Construction of

and pierced with a coiiiiderable number at
Sap-VeflclSi g. . In thcfc,' during the months
of March and July^ there is a watery fabacid
juice, a trtte Sap, untainted by the peculiar
medicinal juices of the Tree ; and at ^other
times they are entirely empty : no tftrpentinc
being ever founfd inthemy unleis forced into
their open mouths from fome other part of the
Tree. The Corona, ki is a thin but very dif-
tindi and elegant circle; dnd the Pith (which'
is not ufua) unlefs in refinous Tree3) is coloured
and clammy. Balfamic Veflels, containing a
peculiar turpentine, a yellow kind, of a coarier
fmell than the reft, rife thro* the Pith. Thefc,
in the cutting, (hed a part of their contehts/
which fpreads amopg the bladders of the Pith j
tfnd gives the whole that colour and that
ilavour^

tiiht.

Explained by thb Microscope. i6i

*- •' ■■ '- '' ' ""'■■' '" ^ "" ■» -- f ■' -■ V ■ > I] -

CHAP. ML

I'articuUrities in the V a s a I n t i m a

of Trees.

1. Their fimpleft State in the Hel'io-

TROPIUM ArBORESCBNS#

As the Vafa intima of Plants have their
proper place in the fubftance of the Blea,
never being found in any part exterior to that,
tho' ibmetimes farther within ; we may judge
that to be their plained and fimpleft ftate where
they are found in a fingle ieries in that part ;
and only there. Such an inftanqe is the Tree
Heliotrope, Plate XXXIX. . This is one of
thofe kinds which are warped to the fun, land
in which all the inner coats conform them-

L felves

i62 The Construction of Timber

felves in fhapc to the exterior (hape of the
Branch : and confequently form in their outlirib^
not circles, but irregular and waved cllipfes.
The Rind and Bark of the Heliotrope, a b,
have nothing in them peculiar, unlefs it be
that the Rind is more uneven than in many
others. The Blea, r, is vaft, ^nd toward the
mner part of it is placed a range of oval
Veffcls, d, filled with a thick, white, acrid
juice, * of the nature of what arc called gum
reiins. Within- thele Vafa intima the Blea is
more compad by far than near the Bark i and
within this lies the Wood,, if, beautifully pierced
with round mouths of Sap-Veflels, which in
July, when I laft cut the Shrub, were fo abun-
dantly replete with a fourifh water, that they
floated' all the fedion with it, and ran over every
way at its edges. The Corona, f^ here -is a
very delicate line, clear, except where the
clufters ojf the Veflels are placed ; and the
Pith, gi is large and plain.

11. Their

Explained by tre jMicroscofe. i6j

Their repeated Series in the Pis-
ciDiA Carthagjenensis.

The fineft view that it is pofllble to obtain
of the Vafa intima of Trees, is that of the
I^ifcidia Erythrina, given before j where t}ie
Veffels were examined as to their ftru(9;ure, in
Plate Xlil. but this other Pifcidia, tho* much
inferior to that, is not without its Angularity
beauty*

We have feen, in the Heliotrope, thefc
Veflcls lodged in their proper place, the Blea ;
Nature has there, allotted to the Shrub a fin*
gle line of them : here we have two, a i} and
the fecond is in a place altogether lingular,
the Corona, The firft and more natural feries
of thcfe Veflels is ranged in the centre of the
Blea : they are oval, large, and full of a juice,
of a ftrong green, utterly unlike and diftinft
from all the other contents of the Branch*
The tepeated feries occupies a cohfiderable fpace
in the plain Corona of the Tree, where they
have alfo loft their oval form* They are per-
fedly cylindric, as is the moft natural fhape of

La thefe

EXFLAlkXP EV THE MiCROSCOFeJ 165

common courfe to fee the Pith of Trees per-'
vaded by longitadinal VeSth, yet the^ Fir,
known by the name of Hemlock Sprucet will
fhew us that not the exteriora alone» but the
intima^ can find their way thither. A ieftion
of this Tree is given, Plate XLI. The exte-
rior range of thefe VefTels is formedi juft where
it (hould be ; in the Blea» a : they are fmalU
hut diftinguiihable enough to an accuflomed
. eye : they are perfedlly round 1 their coats have
a remarkable thickneis; and they are fluffed
full of a firm, rod refip, not a littje refembling
what druggifts call dt'agon's blood. In the Pith
wc meet with VefTels, &, round in their out-
line, perfedly diftind in form from the cells
of the Pith, ^nd filled with this fame red refin^
It is impoffible not to recognise the Vafa intima
in thefe : they flain the whole of the Pith, in
cutting;, with this juice: but the flight colour
that acquires by accident, is very eafily to be
diflinguifhisd from the deep and coarfe contents
of the y.efTels themfelves.

While this fedion is before us, it is impoffible
but we muft flop to admire thg beautiful con-
iiru£tion of the Wpodi ^, formedi of lines drawn

with

i66 The CoNSTRucTiaN of Timber .

v^ith a more than mechanical cxzQnds^ and
oiclofing little cones^ J^ pierced with innu*
merable Sap-Veflcl?^ e. The Corona,^ pro-
tuberates inward > and, in a thin flice^ is rctf
diilina.

mmmmmmmmmmmmmmmmmmmmimi

C H A P. IV.

Particularities of the Coronal Vess els :
Their diftind Appearance in theSuMACH.

IT has been fhewn that the Veflels of the Co*
rona are not different from the feveral Veflels
of the former kinds, only that they are here in
a fmaller compafs> and of lefs flze. They need
not be defcribed particularly after thofej for
greater and lefs is no diflindion in philofbphy ;
nor have thefc any other. Yet, as there is in
Sumach an opportunity laid before the curious

eye

SEjaBOc:E: Srjixrcx JUl

Tl.41

Explained by the Microscope. 167,

45yc of being certified of this truth, it way be
ufefiil^ as well as agreeable, to ihew it.

A fedtioa of this Tree is given, Plate XLIL
^where the firft fight will fliew how much it ap-
proaches to the herbaceous tribeS, in the g^andu-^
lar conftruftion of its Rind, and in its vaft Pith.
Happily in this Tree the Corona makes a more
diftin(ft circle, more defined in itfelf, and more
ifeparate in its parts, than is to oe feen elfe-*
v^hcre. When we have followed the con-
ftrudion df this Shoot from without ; and feea
its brown and hairy Rind, a, lined by the dark
green juicy Bark, ^, and within this the paler,
yet green Blea, c, we difiingui(h very finely the
cllipfes of Wood, J ; and within thefe the
Corona* Its white circle, ^, has let loofe, as*
it were, the clufl:ers, J'; and one of thefe,
feparated, wafhed clean, and viewed by a .
greater power of glafles, appears as at Fig. 2,
where the Rind and Bark, thrown to the ends,
I. 2. (hew dots at 3. which are here the
embryo Vafa exteriora; and larger fpecks at 4.
the interiora. At 5. in that which. is to be
the Blea, are dots, tho' fmall, yet particular in '
colour; and 'tis impolfible, both from that and

L 4 . from

l68 The Construction of Timber

from t)ieir place> to doubt their being Vaik
intima in miniature : and in the central part,
at 6. are Sap-Veflels, whofe openings^ as is
the cafe in matk odier inftances^ are fo big as
almoft to look prepofterous.

The Vafa ezteriora, in the entire fedion, can-
not but be admired ; they are firm, full of a milky
juice ; and when the fedtion^ if of any thicknefs^
has lain but a few minutes, they rife from its
iurface, being too iblid to fhrink with the reft.
In the Pith, at a finall diftance, within the
clufters of the Corona, g^ are to be ieen> very
beautifully, purple Veflels, h, whofe form an4
firudure ihews them Vafa intiinaf

CHAP,

Sttm^cu:

J'l.fi

£ e d c b

EXFLAINEO BV THE Ml^ROSCOPi;i 169

mt!mmtgfifmmmtmmmmmmfmn^^'''r^^'^>^'»'»^'m^^mm^mmmmmmfmm^

CHAP. V.

Of the Diftribution of the Sap- Vessels,
particularly in the Oaks.

TO form a proper judgment of thefc
Vcffels, too much mifunderftood by
many, we can po where follow them better
than in 'the Oak ; the firmeft, ftrongefl^
heavieft of Trees ; yet pierced beyond all others
by thcfe tubes. They have been (hewn in
their natural ftate in Plate IIL in the common
Englifh Oak : and that fize and diftribution
of them, however ftrange it might fecm to an
unaccuflomed eye, is not peculiar to the fingle
fpecies. Nature is uniform in all her works ^
and tho* there be few Trees, if indeed any,
that have thefe openings fo large and numerous
gs the Scarlet andtheEngli(hOak,yct in all fpecies

170 The Construction of Timber* &c,

of that Tree they arc very nearly alike. In the
Scarlet Oak of America, fo pierced with them
jts to be uniit to contain, in vefTels made of it,
any thing but dry goods ; they fland much as
in our Englifh kind, only not quite fo regularly.
A view of this is given, Plate XLIIL There
is a fort of triple row, a b r, formed of them
in the Wood of each feafon, but not corredly.

TheSpanifli Oak affords them in double rows.

In the Ever-gree^pak they have no circular
diredion, but run down obliquely crofs-wife.

In theChefnutOak they are thrown into rays^.
And in the Red Oak, not the Scarlet, crofs*

wife.

But in all thefc fpecies the proj5ortion of
aperture. to folid is very nearly kept up, ex-
cept in the Scarlet, where it is much greater
than in any others. In the reft, where the
VefTels are largeft, there are few eft of them ;
and where fmaller, their number makes amends

for their want of fize.

INDEX.

Sc^iSLLMT O-d^:

-Pl-43

fmmm^

WVHWi

■«i""*i

I N D E X.

CACIA

• Alburnum

Almond
Annona

Arbutus

Afh Maple

A..

Pige
134

44
148

146

136

106

Bark

Bark, its Ufes —
BarkofWaiow —.
Bark of Ozier •—
Bark, Its EHfFerences
Bark of the Service Tree

*•..

38
116

116

118

Blea

E X^

Blea

Blca, its ^Particularities

Blca of the Liriodendron

Blea of the Oleander

Blea of the Nerium Zeylanicum

«lea of Willow

Blea of Ozier —

Blea of the Ephedra

Branches

Caragna

Circle of Propagation
Circles in Arbutus
Circles in Thuya Chinenfis

Ciftus Laurifolia

Cluflers in Magnolia

Cornus

Corona

Corona^ its-Veflels — ^

_ •

Corona, its Conftruftion
Corona, its Parts — .

Corona, its VefTels ,

Corona, its Partioularities — -
Corona of the Ciftus Laurifolia
Corona of Magnolia

Page

—— ' 121-

— — 122

— 124

125

' 416

— 417
— — 127

^3S

SS
130

138
140
142
130

55—140
140

5«
58

140
140.
141

Corona

I iJ D E X.

Page

Corona of Stapfayksa >■ ■ ■ ■ — 143

Corona of Plucknctia — — 144

Corona of the Oak ^ i ■ ■ , ■ — — 59

Corona of the Bocconia — : ■ ■ - 60

Cortex — * — 4^

Cortex» its Ufcs —— : 38

CuprdTus Am^ " ■ f J 53

■Cutting Engine — *-^ * . j? 4

Cyprcfe . : r — ! — 153

Dog-Wood — — ^^-^ 130

Dog-Rofe — »•— r; l'«

Engine Cutting

Ephedra < ■ ■« - ■ !!r~T 1^*7

Growth "" ■ ■ ^ ■ ■ ] r "~ ] 97

Hemlock Fif ^ *— -■" ^— ^ 164

Heliotropium

I N D E X^

Page

Hcliotropium Arborefcens -~ ^ ■ ■■■ ■■ 161

Larix — . —— — 154

JUber ■ f — — 41

Xignum — ^— ^ — — * 51

Liriodeadron ^— ■ — — 122

Magnolia ^— ■ > ■ 142

MeduUa — i— ^— - 65

• - _

Microfcopc — — — — — u

— 4

Nerium Oleander ■ » 124

Neriufi^ Zeylanicum — - — — . J25

Oak, Efigliih — . ■■ ■ — 169

Oak, American — . ' — ■ 170

Oak, Scarlet — ' — 170

Oak, Red — ■ ■ 170

Oak, Spaaifli -^ — ^ TT ^7^

Oak,

N D E X.

Oak, Willow
Oak, Chefnut
Oak, Evergreen

Oleander

Page
170
170
170

124

Parts to obtain
Petraea —
Pinus Ccmbra
Piicidia Carthagenenfis

Pith — .—

Pith, it5 Origin
Pith, its Nature —
Pith, itsUfcs ~

Pith of the Annona
Pith of the Almond
Pith of the Petraea

Plucknetia

Quercus AngUca
Quercus Americana

Quercus Segipervirens
•Quercus Caflaneifolia

65.

149
163

•146

66
67

146

147

144

169

• 170

170

Quercus

INDEX.

_ Page

Quercus Salidfolia ■ ^ j^5

Querctts Hifpanica •— «— ^.._ lyo

Qiiercu8 Rabra ^— * . .^ «. j^^

Kind -^— « i^—^ .. 291

Rind» its Differences ■ ■ no

Rind of Dog-Rofe > .. 1 1 i

Rind, its U&s — « — — ^ x

Rind, its Conftrudion ■ -^. 2^

Robinta ' ^^ ^^ j^^

Rofa Canina — • --^ •-*- 1 1 ^

Sap-Veffcls — . 8 J

Sap-Vefiels, filling of them -*- i pi

Sap^Veffels in Oa^s » ■ ijq

Seafbnsj Circles of ■ . 1^2

Shoots — ■ ■■ .... I or

Shoot, its Growth 1 -i *«. 10 c

Staphylaea — -« «« _ i^^

Sumach -^ ■ •»» 1^55

Tanacetum

i N

^anacetiim Frutican^

'I'liuya Chinerifis

Timber, its Parts

Trees, their Veflels
Trees, their Growth

rfit

Pigh
156

■•

r-' ' *- *

Va(a ■' ""•^ ' ; '

Vafa Propria E:^teriora *— -^
Vafa Propi;ia Interiora •^^— —

Vafa Propria Intima ■■ ' ^ • . —

Vafa Suceofa -it- — ,. .^

Vafa Exteriora in Cyprefs -^^ •?—
Vafa Interiora in Larix " -^

Vafa Interiora in Tanacetum Fruticans
Vafa Interiora in Pinus Ccmbra -^
Vafa Intima . ^s^^ ■ <" '^ -i-

Vala Intima in Hjeliotrope — ^
Vafa Ifttima in Piifcidia Carth^genenfis
Vafa Intima in Hemlock Fir . -^
Vafa Gorotialia - — ■ . -^

Vafa Coronalia in Sumach ^-fi*^
V^eiTels of Trees ..i^i^.^ .a-

Veflels Exterior - • ' ^ ■ ' ^ ^ • —

VefTels interior -i— *«3 — -

Veflels Innermoft -?-* *-^

72.

78.

72-

78.
82^

72
■152.

•154

M4
156

158

161
i6r
163
164
94

196

152

154^
161

Veflels

I (

N D

Veffcls Sap
VefTels Coronal

3?.

Wood ' —
Wood, its Conftru^on
Wood, its Vcffels
Wood of the Dog-Wopd
Wood of the Acacia
Wood of the Robinia
Wood of PearrTrec r
Wood of B^uhinia

51'

130

13d
J 34

52
53

P I R E G-

^•"

DIRECTIONS to the Binder,

Plate

I. io face * -r

JI. to face —

III. to face —

IV. to face -

V. to face

VI. to face
Vn. to face

VIII. to face

IX. /a y^^

X. to face

XI. /tf yirf — —

XII. to face •

XIII. and XIIL repeated, to face

XIV. and XIV. repeated, to face

XV. , to face — — •

XVI. to face

XVII. to face

XVIII. to face

XIX. /(? y^^^:^

XX. to face

XXI. to face

XXII. to face *

\ I

■pMM

86
90

Page

54
62

—87

-92

102

loS*

' 114
118

122

124

126

Plate

filRECtlONS to the BiNfiEii

Plate

XXIII. tp face '

XXIV. to fate

XXV. ' to face -
XXVJ. to/^ce

XXVII. id fate

XXVIII. to face

XXIX. to face

XXX. fo face

XXXI. to face
XXXn. to face

XXXIII. to face

XXXIV. to face

XXXV. to face

XXXVI. tofaee

XXXVII. tofaee

XXXVIII. tofaee

XXXIX. to face
XL. to face •
XLI. to face
XLII. to- face -
XLln. to face

i«M

J^i*m

mUt

ti^m^alUm

Page
128I
131

134
136

138
140
142

143
144

146

148

153

156
160
162

164
1 66

16^

IJ9

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